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1.
J Dairy Sci ; 103(11): 10856-10861, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32952020

RESUMO

Our objective was to determine the effect of increasing the interval from induction of ovulation to timed artificial insemination (TAI) on fertility by decreasing the interval from TAI to ovulation using sexed semen within a synchronized breeding program. Our hypothesis was that induction of ovulation earlier relative to TAI would increase pregnancies per artificial insemination (P/AI). Primiparous Holstein cows from 3 commercial dairy farms in the United States were submitted to a Double-Ovsynch protocol for first service as follows: Pre-Ovsynch (GnRH; 7 d, PGF2α; 3 d, GnRH), followed 7 d later by Breeding-Ovsynch [GnRH (G1); 7 d, PGF2α; 24 h, PGF2α], followed by the last GnRH treatment (G2), which varied between treatments, and TAI. To vary the interval between G2 and TAI, cows were randomized to 2 treatments to receive G2 either 16 (G2-16; n = 373) or 24 (G2-24; n = 357) h before TAI, which was fixed at 48 h after the second PGF2α treatment of the Breeding-Ovsynch portion of the protocol. All cows were inseminated with sexed semen, and each herd used sires of their choosing, which were randomly allocated between treatments. Pregnancy diagnosis was conducted by herd veterinarians using transrectal ultrasonography. In disagreement with our hypothesis, G2-24 cows had fewer P/AI than G2-16 cows at 34 ± 3 d (44 vs. 50%) and 80 ± 17 d (41 vs. 48%) after TAI. Pregnancy loss (5 vs. 6%) and fetal sex ratio (92:8 vs. 90:10, female:male) did not differ between treatments for G2-16 and G2-24 cows, respectively. Thus, we reject our hypothesis and conclude that induction of ovulation earlier relative to TAI with sexed semen for first service after a Double-Ovsynch protocol decreased P/AI in primiparous Holstein cows.


Assuntos
Bovinos/fisiologia , Sincronização do Estro/métodos , Inseminação Artificial/veterinária , Indução da Ovulação/veterinária , Ovulação/efeitos dos fármacos , Pré-Seleção do Sexo/veterinária , Animais , Dinoprosta/administração & dosagem , Dinoprosta/farmacologia , Feminino , Fertilidade/efeitos dos fármacos , Hormônio Liberador de Gonadotropina/farmacologia , Inseminação Artificial/métodos , Masculino , Indução da Ovulação/métodos , Ocitócicos/administração & dosagem , Ocitócicos/farmacologia , Gravidez , Resultado da Gravidez/veterinária , Progesterona/administração & dosagem , Progesterona/farmacologia , Progestinas/administração & dosagem , Progestinas/farmacologia , Sêmen , Fatores de Tempo
2.
Artigo em Inglês | MEDLINE | ID: mdl-20528403

RESUMO

This paper provides a welfare assessment of the new Taiwan National Health Insurance (NHI) co-payment policy, enacted July 15, 2005. This policy creates a pricing mechanism designed to entice patients to first seek outpatient care at local clinics rather than hospitals. Our empirical findings suggest that while the new policy results in a net welfare gain, it is far less than the expected annual growth in NHI medical expenditure. Thus, additional policy changes will be required to deal with Taiwan's NHI future financial shortfalls.

3.
J Thromb Haemost ; 4(1): 129-36, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16409462

RESUMO

BACKGROUND: A deficiency in the plasma metalloprotease ADAMTS-13 is associated with deposition of microvascular thrombi that cause thrombotic thrombocytopenic purpura. Current assays for ADAMTS-13 are technically complex and time-consuming. The objective of this study is to devise a rapid and sensitive assay for ADAMTS-13 activity in plasma and verify the site of cleavage. METHOD: A new enzyme-linked substrate, which contains a core ADAMTS-13-specific peptide conjugated to horseradish peroxidase (HRP) at the N-terminus, and labeled with biotin at the C-terminus, was constructed. After cleavage of this substrate by plasma ADAMTS-13 and removal of uncleaved substrate by adsorption with streptavidin-agarose, ADAMTS-13 activity was quantitated by determining the unadsorbed HRP activity remaining in solution. Levels of inhibitory antibodies in test plasma were also determined by measuring the residual ADAMTS-13 activity after varying amounts of test plasma were incubated with a known amount of ADAMTS-13. RESULTS: Plasma ADAMTS-13 activity was readily determined in approximately 60 min (coefficient of variation 5.8%) using 1 microL of test plasma. Amino acid sequencing of the cleavage product confirmed that cleavage occurred at the Tyr1605-Met1606 bond in the substrate. ADAMTS-13 activities in the plasma of five TTP patients were below 2%. Inhibitory antibody titers in these samples varied from undetectable to 81 BU mL(-1). CONCLUSION: The HRP-linked substrate provides a rapid, sensitive, and reproducible way of determining the levels of ADAMTS-13 activity and inhibitory antibodies in plasma.


Assuntos
Proteínas ADAM/sangue , Ensaios Enzimáticos Clínicos/métodos , Púrpura Trombocitopênica Trombótica/diagnóstico , Proteínas ADAM/metabolismo , Proteína ADAMTS13 , Sítios de Ligação , Biotinilação , Ensaios Enzimáticos Clínicos/normas , Peroxidase do Rábano Silvestre , Humanos , Fragmentos de Peptídeos , Fotometria , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
4.
Biochemistry ; 40(50): 15341-8, 2001 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-11735417

RESUMO

hK4 (prostase, KLK4), a recently cloned prostate-specific serine protease and a member of the tissue kallikrein family, is a zymogen composed of 228 amino acid residues including an amino-terminal propiece, Ser-Cys-Ser-Gln-. A chimeric form of hK4 (ch-hK4) was constructed in which the propiece of hK4 was replaced by that of prostate-specific antigen (PSA) to create an activation site susceptible to trypsin-type proteases. ch-hK4 was expressed in Escherichia coli, isolated from inclusion bodies, refolded, and purified with an overall yield of 25%. The zymogen was readily self-activated during the refolding process to generate an active form (21 kDa) of hK4 (rhK4). rhK4 cleaved the chromogenic substrates Val-Leu-Arg-pNA (S-2266), Pro-Phe-Arg-pNA (S-2302), Ile-Glu-Gly-Arg-pNA (S-2222), and Val-Leu-Lys-pNA (S-2251), indicating that rhK4 has a trypsin-type substrate specificity. The rhK4 was inhibited by aprotinin (6 kDa), forming an equimolar 27 kDa complex. rhK4 readily activated both the precursor of PSA (pro-PSA) and single chain urokinase-type plasminogen activator (scuPA, pro-uPA). rhK4 also completely degraded prostatic acid phosphatase but failed to cleave serum albumin, another protein purified from human seminal plasma. These results indicate that hK4 may have a role in the physiologic processing of seminal plasma proteins such as pro-PSA, as well as in the pathogenesis of prostate cancer through its activation of pro-uPA.


Assuntos
Calicreínas , Antígeno Prostático Específico/metabolismo , Próstata/enzimologia , Precursores de Proteínas/metabolismo , Proteínas Tirosina Fosfatases/metabolismo , Serina Endopeptidases/química , Serina Endopeptidases/metabolismo , Ativador de Plasminogênio Tipo Uroquinase/metabolismo , Fosfatase Ácida , Sequência de Aminoácidos , Sítios de Ligação , Humanos , Concentração de Íons de Hidrogênio , Masculino , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/etiologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas de Plasma Seminal/metabolismo , Serina Endopeptidases/genética , Especificidade por Substrato
5.
Blood ; 98(6): 1662-6, 2001 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11535495

RESUMO

von Willebrand factor (vWF) is synthesized in megakaryocytes and endothelial cells as a very large multimer, but circulates in plasma as a group of multimers ranging from 500 to 10 000 kd. An important mechanism for depolymerization of the large multimers is the limited proteolysis by a vWF-cleaving protease present in plasma. The absence or inactivation of the vWF-cleaving protease results in the accumulation of large multimers, which may cause thrombotic thrombocytopenic purpura. The vWF-cleaving protease was first described as a Ca(++)-dependent proteinase with an apparent molecular weight of approximately 300 kd. Thus far, however, it has not been isolated and characterized. In this study, the purification of human vWF-cleaving protease from a commercial preparation of factor VIII/vWF concentrate by means of several column chromatographic steps, including 2 steps of heparin-Sepharose column, is reported. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the anion exchange and gel filtration column fractions showed that the vWF-cleaving protease activity corresponded to a protein band of 150 kd. After reduction, it migrated with an apparent weight of 190 kd. The amino terminal sequence of the 150-kd band was AAGGIL(H)LE(L)L(D)AXG(P)X(V)XQ (single-letter amino acid codes), with the tentative residues shown in parentheses. A search of the human genome sequence identified the vWF-cleaving protease as a new member of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin type I motif) family of metalloproteinase. An active site sequence of HEIGHSFGLEHE (single-letter amino acid codes) was located at 150 residues from the N terminus of the protein.


Assuntos
Metaloendopeptidases/química , Metaloendopeptidases/isolamento & purificação , Proteínas ADAM , Proteína ADAMTS13 , Sequência de Aminoácidos , Cromatografia em Gel , Cromatografia por Troca Iônica , Humanos , Dados de Sequência Molecular
6.
Health Prog ; 79(4): 104, 103, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-10181591

RESUMO

In 1995, Holy Family Hospital, in Prince Albert, Saskatchewan, Canada, began the process of closing its doors. Holy Family Hospital, operated by the Sisters of Charity of the Immaculate Conception, had been tending the sick for 87 years, and was a large employer in the area. Its roots ran deep in the community. In September 1997, Sr. McMullen spoke to hospital employees, provincial and civic leaders, and community religious figures at a banquet marking the culmination of the long and difficult process.


Assuntos
Catolicismo , Fechamento de Instituições de Saúde , Hospitais Religiosos/organização & administração , Relações Comunidade-Instituição , Objetivos Organizacionais , Saskatchewan , Mudança Social
8.
Health Prog ; 77(1): 28-30, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-10154457

RESUMO

The private association of the Christian faithful (PACF) and private juridic person (PJP) are two lay sponsorship options for healthcare organizations that find traditional sponsorship unavailable. Today two questions relate to these models: Are the PACF and the PJP still realistic and attractive models of sponsorship? Can Catholic identity be maintained in them? Last summer CHA surveyed the seven member organizations that use either the PACF or the PJP as sponsorship models. In addition, CHA conducted four site visits, which corroborated the survey findings. Most respondents said their organizations had adopted the lay model as a means of remaining Catholic after their original sponsors withdrew. Most said they had a good relationship with the local diocese, although formal meetings with the diocesan leaders were infrequent. Each organization had a clearly articulated mission and reinforced their mission and values in various ways. Leadership development appeared somewhat weak. Some respondents spoke favorably of the PACF and PJP models of sponsorship, but others saw limitations, including isolation, lack of clarity in reporting mechanisms between the organization and the diocese, and lack of board education about the models. Even those who saw a future for lay sponsorship on the PACF and PJP models said that, although it is important for Catholic healthcare to develop lay leadership, these models are not promising steps in that direction.


Assuntos
Catolicismo , Hospitais Religiosos/organização & administração , Modelos Organizacionais , Propriedade/organização & administração , Constituição e Estatutos , Conselho Diretor , Relações Interinstitucionais , Liderança , Objetivos Organizacionais , Valores Sociais , Inquéritos e Questionários , Estados Unidos
9.
Genomics ; 29(1): 179-86, 1995 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-8530069

RESUMO

cDNAs encoding the small subunit of bovine and human DNA polymerase delta have been cloned and sequenced. The predicted polypeptides, 50,885 and 51,289 Daltons, respectively, are 94% identical, similar to the catalytic subunits. The high degree of conservation of the polypeptides suggests an essential function for the small subunit in the heterodimeric core enzyme. Although the catalytic subunit of DNA polymerase delta shares significant homology with those of the herpes virus family of DNA polymerases, the small subunit of mammalian DNA polymerase delta is not homologous to the small subunit of either herpes simplex virus type 1 DNA polymerase (UL42 protein) or the Epstein-Barr virus DNA polymerase (BMRF1 protein). Searches of the protein databases failed to detect significant homology with any protein sequenced thus far. PCR analysis of DNA from a panel of human-hamster hybrid cell lines localized the gene (POLD2) for the small subunit of DNA polymerase delta to human chromosome 7.


Assuntos
Bovinos/genética , Cromossomos Humanos Par 7 , DNA Polimerase III/genética , DNA Polimerase Dirigida por DNA/genética , Hominidae/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Mapeamento Cromossômico , Cricetinae , Primers do DNA , DNA Complementar , Herpesvirus Humano 4/enzimologia , Herpesvirus Humano 4/genética , Humanos , Células Híbridas , Substâncias Macromoleculares , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Simplexvirus/enzimologia , Simplexvirus/genética , Células Tumorais Cultivadas
10.
Protein Sci ; 4(4): 740-6, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7613471

RESUMO

The locations of disulfide bonds and free cysteines in the heavy and light chains of recombinant human factor VIII were determined by sequence analysis of fragments produced by chemical and enzymatic digestions. The A1 and A2 domains of the heavy chain and the A3 domain of the light chain contain one free cysteine and two disulfide bonds, whereas the C1 and C2 domains of the light chain have one disulfide bond and no free cysteine. The positions of these disulfide bonds are conserved in factor V and ceruloplasmin except that the second disulfide bond in the A3 domain is missing in both factor V and ceruloplasmin. The positions of the three free cysteines of factor VIII are the same as three of the four cysteines present in ceruloplasmin. However, the positions of the free cysteines in factor VIII and ceruloplasmin are not conserved in factor V.


Assuntos
Cisteína/química , Dissulfetos/química , Fator VIII/química , Sequência de Aminoácidos , Cromatografia Líquida de Alta Pressão , Humanos , Iodoacetamida , Dados de Sequência Molecular , Peptídeos/química , Desnaturação Proteica , Proteínas Recombinantes/química , Análise de Sequência
11.
J Biol Chem ; 269(26): 17626-34, 1994 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-8021272

RESUMO

The kappa B enhancer element regulates expression of many genes involved in immune responses and other processes. kappa B motif binds a number of proteins, some but not all, are related to the NF-kappa B family of transcription factors. We have previously identified a 65-kDa phosphoprotein that is specifically recognized by the kappa B motif (Ostrowski, J., Sims, J. E., Sibley, C. H., Valentine, M. A., Dower, S. K., Meier, K. E., and Bomsztyk, K. (1991) J. Biol. Chem. 266, 12722-12733). This protein is closely associated with a serine/threonine kinase that is responsive to treatment of cells with interleukin-1 and other agents. We report here purification, cloning, and expression of this kappa B motif-binding phosphoprotein. The primary structure deduced from the isolated murine cDNA, identifies the protein as the homolog of the human heterogeneous nuclear ribonucleoprotein K protein. Antipeptide antibodies and expression of the cloned cDNA in Escherichia coli, demonstrated that the K protein is the authentic phosphoprotein that binds the kappa B motif in vitro. We also demonstrate that the in vitro phosphorylation of the natural and the recombinant K proteins by the associated kinase is stimulated by the kappa B motif.


Assuntos
DNA/metabolismo , NF-kappa B/metabolismo , Fosfoproteínas/isolamento & purificação , Ribonucleoproteínas/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Sítios de Ligação , Caseína Quinase II , Cromatografia de Afinidade , Cromatografia por Troca Iônica , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Ribonucleoproteínas Nucleares Heterogêneas , Humanos , Camundongos , Dados de Sequência Molecular , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Ribonucleoproteínas/genética , Células Tumorais Cultivadas
12.
Agents Actions Suppl ; 38 ( Pt 2): 219-30, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1462829

RESUMO

In recent years, extensive knowledge has been obtained on the structure/function relationships of blood coagulation proteins. In this overview, we present recent developments on the structure/function relationships of the contact activation proteins: factor XII, high molecular weight kininogen, prekallikrein, and factor XI, with the emphasis on the localization of domains on these proteins that are involved in the interaction with activators, substrates and cofactors.


Assuntos
Fatores de Coagulação Sanguínea/fisiologia , Sequência de Aminoácidos , Sítios de Ligação , Fatores de Coagulação Sanguínea/química , Ativação Enzimática , Fator XI/química , Fator XI/fisiologia , Fator XII/química , Fator XII/fisiologia , Humanos , Cininogênios/química , Cininogênios/fisiologia , Modelos Estruturais , Dados de Sequência Molecular , Pré-Calicreína/química , Pré-Calicreína/fisiologia , Conformação Proteica
14.
Biochemistry ; 30(8): 2050-6, 1991 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-1998666

RESUMO

The location of 16 of the 18 disulfide bonds in human plasma prekallikrein was determined by amino acid sequence analysis of cystinyl peptides produced by chemical and enzymatic digestions. A unique structure, named the apple domain, was established for each of the four tandem repeats in the amino-terminal portion of the molecule. The apple domains (90 or 91 amino acids) contain 3 highly conserved disulfide bonds linking the first and sixth, second and fifth, and third and fourth half-cystine residues present in each repeat. The fourth tandem repeat contains an extra disulfide bond that forms a second small loop within the apple domain. The carboxyl-terminal portion of plasma prekallikrein containing the catalytic region of the molecule was found to have disulfide bonds located in positions similar to those of other serine proteases.


Assuntos
Pré-Calicreína , Sequência de Aminoácidos , Cromatografia Líquida de Alta Pressão , Brometo de Cianogênio , Dissulfetos/análise , Humanos , Dados de Sequência Molecular , Fragmentos de Peptídeos/isolamento & purificação , Pré-Calicreína/isolamento & purificação , Conformação Proteica , Tripsina
15.
Biochemistry ; 30(8): 2056-60, 1991 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-1998667

RESUMO

Factor XI is a plasma glycoprotein that participates in the blood coagulation cascade. Of the 19 disulfide bonds present in each of the subunits of the human protein, 16 were determined by amino acid sequence analysis of peptide fragments produced by chemical and enzymatic digestion. Four apple domains of 90 or 91 amino acids were identified in the tandem repeats present in the amino-terminal portion of each subunit of factor XI. The disulfide bonds in the carboxyl-terminal portion of the molecule were similar to those in the catalytic region of other serine proteases. The two identical subunits of factor XI were connected by a single disulfide bond at Cys321 linking each of the fourth apple domains while each of the Cys residues at position 11 in the first apple domains forms a disulfide bond with another Cys residue.


Assuntos
Fator XI/química , Sequência de Aminoácidos , Cromatografia Líquida de Alta Pressão , Brometo de Cianogênio , Dissulfetos/análise , Fator XI/isolamento & purificação , Humanos , Dados de Sequência Molecular , Peso Molecular , Fragmentos de Peptídeos/isolamento & purificação , Conformação Proteica , Tripsina
17.
Biochemistry ; 29(32): 7366-72, 1990 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-2223768

RESUMO

The major pepsin inhibitor from Ascaris suum was isolated by affinity chromatography and chromatofocusing. Its amino acid sequence was determined by automated Edman degradation of peptide fragments. Peptides were produced by chemical and enzymatic cleavage of pyridylethylated protein and were purified by reverse-phase high-performance liquid chromatography. The inhibitor consists of 149 residues with the following sequence: QFLFSMSTGP10FICTVKDNQV20FVANLPWTML30EGDDIQVGKE40 FAARVEDCTN50VKHDMAPTCT60KPPPFCGPQD70MKMFNFVGCS80VLGNKLFIDQ90KYVRDLTAK D100 HAEVQTFREK110IAAFEEQQEN120QPPSSGMPHG130AVPAGGLSPP140PPPSFCTVQ149. It has a molecular weight of 16,396. All cysteines are engaged as disulfide bonds: Cys(13)-Cys(59), Cys(48)-Cys(66), and Cys(79)-Cys(146). The protein is probably composed of two domains connected by a short hydrophobic region. This is the first aspartyl protease inhibitor of animal origin that has been sequenced. The sequence has no significant homology with any other known protein.


Assuntos
Ascaris/análise , Pepsina A/antagonistas & inibidores , Sequência de Aminoácidos , Animais , Cromatografia de Afinidade , Intestinos/parasitologia , Dados de Sequência Molecular
18.
Biochem Biophys Res Commun ; 170(1): 153-61, 1990 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-2372284

RESUMO

Human platelet glycoprotein V (Mr 82,000) is a surface glycoprotein and a substrate for thrombin, undergoing proteolytic cleavage by thrombin and releasing a soluble fragment, glycoprotein Vfl (Mr 69,000). It does not appear to be the receptor for thrombin's agonist effect on platelets. A congenital platelet disorder, Bernard-Soulier syndrome, is marked by a deficiency of glycoprotein V and two other surface glycoproteins, Ib-IX. The latter two, Ib-IX, constitute the platelet receptor for von Willebrand factor, mediate arterial platelet adhesion, and contain unique 24-amino acid sequences, termed "leucine-rich glycoprotein" segments. The segments relate to adhesive function and distinguish the leucine-rich glycoprotein family. Surface glycoprotein V is not physically associated with Ib-IX nor does it bind to von Willebrand factor. To date, no common denominator has been found that explains the combined deficiency of glycoproteins V and Ib-IX in Bernard-Soulier syndrome. This study describes the isolation of glycoprotein V/anti-glycoprotein V antibody and the analysis of three glycoprotein V peptides that contain "leucine-rich" sequences. Therefore, glycoprotein V shares the "leucine-rich" structure with platelet glycoproteins Ib-IX and belongs to the family of leucine-rich glycoproteins.


Assuntos
Adesividade Plaquetária , Glicoproteínas da Membrana de Plaquetas/isolamento & purificação , Sequência de Aminoácidos , Humanos , Dados de Sequência Molecular , Glicoproteínas da Membrana de Plaquetas/análise , Glicoproteínas da Membrana de Plaquetas/imunologia
19.
Biochemistry ; 28(2): 674-9, 1989 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-2653426

RESUMO

The amino acid sequence of a protease, protein C activator, from Agkistrodon contortrix contortrix venom was determined. Peptide fragments obtained by chemical or enzymatic cleavage of the S-carboxymethylated protein were purified by gel filtration and reverse-phase high-performance liquid chromatography. The present study demonstrates that protein C activator from A. contortrix contortrix venom is a trypsin-type serine protease that is composed of 231 residues with a molecular weight of 25,095 for the polypeptide portion of the molecule. By analogy to the mammalian serine proteases, the catalytic triad in venom protein C activator consists of His-40, Asp-85, and Ser-177. The protein also contains three N-linked glycosylation sites at Asn-21, Asn-78, and Asn-129. The amino acid sequence of protein C activator exhibits a high degree of sequence identity with other snake venom proteases: 73% with batroxobin, 68% with flavoxobin, and 55% with Russell's viper venom factor V activator.


Assuntos
Venenos de Crotalídeos/análise , Oligopeptídeos/isolamento & purificação , Proteína C/metabolismo , Sequência de Aminoácidos , Animais , Cromatografia Líquida de Alta Pressão , Dados de Sequência Molecular , Fragmentos de Peptídeos/análise , Peptídeo Hidrolases , Homologia de Sequência do Ácido Nucleico
20.
J Biol Chem ; 263(35): 18657-63, 1988 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-2974032

RESUMO

Five proteins from human placenta capable of inhibiting pancreatic phospholipase A2 were purified. Two of these proteins were identified as lipocortins I and II. The other three proteins were immunologically distinct from lipocortins I and II and had apparent subunit molecular masses of 32, 33, and 73 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amino acid sequence analysis of peptides produced by cyanogen bromide digestion indicated sequence homology of these proteins with lipocortin I and the heavy chain subunit of lipocortin II. Two of these proteins were identified as endonexin II and 67-kDa calelectrin. The third protein appears to be the human form of bovine endonexin I, also characterized as porcine protein II. Sedimentation equilibrium analysis of lipocortin I, endonexin I and II, and the 67-kDa calelectrin suggested monomer-dimer equilibria with dissociation constants in the range of 0.33-1.3 X 10(-3) M and monomer molecular masses of 38,050, 36,400, 36,850, and 73,610 Da, respectively. Self-association of lipocortin II was described by dimerization of a protomer (K12 = 5.3 x 10(-7) M), followed by an indefinite self-association of the dimer (isodesmic dissociation constant, Kiso = 3.6 x 10(-6) M). The protomer molecular mass was 48,800 Da, consistent with a heterodimeric structure composed of one heavy (38,600 Da) and one light (10,944 Da) chain as previously characterized for lipocortin II. Sedimentation equilibrium analysis of mixtures of individual protein inhibitors and purified pancreatic phospholipase A2 indicated weak association between enzyme and inhibitor (Kd greater than or equal to 3 x 10(-5) M), insufficient to account for the observed inhibition of enzyme activity.


Assuntos
Glicoproteínas/farmacologia , Fosfolipases A/antagonistas & inibidores , Fosfolipases/antagonistas & inibidores , Placenta/enzimologia , Anexina A5 , Anexinas , Proteínas de Ligação ao Cálcio/farmacologia , Humanos , Peso Molecular , Fosfolipases A2 , Ultracentrifugação
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