RESUMO
Edible bird's nest contains lots of glycoproteins. The glycosylation inhomogeneity for glycoprotein often results in wide range of molecular weight and the difficulty for protein separation and charaterization. In this paper, proteins in the edible bird's nest were extracted using multiple extractions, and then digested by PNgase F and trypsin. The digest mixture was separated with HPLC, and peptides were identified based on MS/MS data searching. The results indicated that the extracted proteins were amount to 79.7% of total protein in the edible bird's nest. More than 20 species of peptides in the digested mixture were identified. The sequences of these peptides showed similarity with some proteins from Swiss-prot. The research indicated that deglycosylation, tryptic digestion coupled with HPLC-MS/MS is a proper strategy for characterization of proteins in the edible bird's nest.
Assuntos
Animais , Sequência de Aminoácidos , Aves , Cromatografia Líquida de Alta Pressão , Glicoproteínas , Química , Espectrometria de Massas , Medicina Tradicional Chinesa , Fragmentos de Peptídeos , Química , Metabolismo , ProteóliseRESUMO
A fraction named GFC-1 with high antioxidant activities in vitro was isolated from the enzymatic hydrolysates of roasted pills of Asini Corii Colla, and the peptides in this fraction were identified. The enzymatic hydrolysates were isolated and purified with anion exchange chromatography and Sephadex G-25 filtration chromatography successively. GFC-1, a fraction isolated from the hydrolysates, exhibited the highest DPPH and ABTS scavenging capacity (DPPH 47. 95% at 2.0 g x L(-1) and ABTS 97.20% at 0.40 g x L(-1). Nine peptides from GFC-1 were identified by LC-ESI-MS/MS coupled with TurboSEQUEST search software and Swiss-Prot data base, and a high repetition core sequence GPAGPP*GPP* was also found.
Assuntos
Animais , Antioxidantes , Química , Equidae , Hidrólise , Espectrometria de Massas , Peptídeos , Química , Hidrolisados de Proteína , Química , Pele , QuímicaRESUMO
The aim is to determine the primary structure of a new hirudin and reteplase fusion protein (HV12p-rPA) by LC-ESI-MS/MS spectrometry. The molecular weight of the hirudin and reteplase fusion protein (HV12p-rPA) was measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The HV12p-rPA was digested with trypsin and chymotrypsin separately and the peptides in the digest mixtures were identified by LC-ESI-MS/MS. The molecular weight of HV12p-rPA was 41,472 Da, which was in accordance with the theoretical value. The peptide fragments of HV12p-rPA digested with trypsin were identified by LC-ESI-MS/MS spectrometry and the results indicated that the fusion protein contained r-PA. Then, the peptides of HV12p-rPA digested with chymotrypsin were identified by the same method. The results indicated that the fusion protein contained HV12p and the linker-containing peptide, DEGGGSY. MASDF and LDWIRDNMRP were identified as the N-terminal and C-terminal containing peptides in the chymotryptic digest mixture of the fusion protein. All of the Xcorr values exceeded 1.5, some of which were above 3.0, showing that the results were correct and credible and a sequence coverage of 85% was achieved. HPLC/MS analysis coupled with uncompleted digestion indicated that all these peptides were arranged with the correct order as expected. Thus, sequence of the fusion protein was confirmed and it was consistent with our design in upstream construction.
Assuntos
Sequência de Aminoácidos , Cromatografia Líquida , Métodos , Quimotripsina , Química , Fibrinolíticos , Química , Hirudinas , Química , Dados de Sequência Molecular , Peso Molecular , Fragmentos de Peptídeos , Proteínas Recombinantes de Fusão , Química , Proteínas Recombinantes , Química , Espectrometria de Massas por Ionização por Electrospray , Métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Métodos , Espectrometria de Massas em Tandem , Métodos , Ativador de Plasminogênio Tecidual , Química , Tripsina , QuímicaRESUMO
Streptomyces coelicolor is the model species among streptomycetes. Until now, proteomic analyses of S. coelicolor have been conducted using two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry method, few integral membrane proteins were identified due to the hydrophobic and low-abundance nature of these proteins. In this work, 154 possible inner membrane proteins from S. coelicolor were identified using high pH-proteinase K sample preparation method and multidimensional protein identification technology, among them 44 are integral membrane proteins containing at least one transmembrane domain, most peptides and their corresponding proteins were identified experimentally for the first time.
Assuntos
Proteínas de Bactérias , Membrana Celular , Química , Genoma Bacteriano , Genética , Espectrometria de Massas , Métodos , Proteínas de Membrana , Proteoma , Genética , Streptomyces coelicolor , Química , GenéticaRESUMO
A new method for preparation of Hb solution free of stromal lipid was described. Almost all the lipid in fresh hemolysate of bovine red blood was removed with hydrophobic interaction chromatography (HIC) in the presence of 2% PEG4000, 5% PEG4000, 2%PEG10000 or 5%PEG10000. With the adding of 5%PEG4000, the 80% of recovery of Hb in HIC was obtained and the maximum lipid absorbed by hydrophobic medium, butyl agarose -6B was 86.6 mg/mL. The activity (P50) of hemoglobin preparation was 3386.4 Pa torrs, and the Hill number was 2.54, which were near to that of the native red blood cells. The mechanism of removing lipid by HIC and the function of PEG in the process were discussed.