RESUMO
Acyl-CoA-binding protein (ACBP) is a 10 kDa protein characterized in vertebrates. We have isolated two ACBP homologues from the yeast Saccharomyces carlsbergensis, named yeast ACBP types 1 and 2. Both proteins contain 86 amino acid residues and are identical except for four conservative substitutions. In comparison with human ACBP, yeast ACBPs exhibit 48% (type 1) and 49% (type 2) conservation of amino acid residues. The amino acid sequence of S. carlsbergensis ACBP type 1 was found to be identical with the one ACBP present in Saccharomyces cerevisiae. A recombinant form of this protein was expressed in Escherichia coli and S. cerevisiae, purified, and its acyl-CoA-binding properties were characterized by isoelectric focusing and microcalorimetric analyses. The yeast ACBP was found to bind acyl-CoA esters with high affinity (Kd 0.55 x 10(-10) M). Overexpression of yeast ACBP in S. cerevisiae resulted in a significant expansion of the intracellular acyl-CoA pool. Finally, Southern-blotting analysis of the two genes encoding ACBP types 1 and 2 in S. carlsbergensis strongly indicated that this species is a hybrid between S. cerevisiae and Saccharomyces monacensis.
Assuntos
Acil Coenzima A/metabolismo , Proteínas de Transporte/metabolismo , Saccharomyces/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Southern Blotting , Calorimetria , Proteínas de Transporte/química , Proteínas de Transporte/genética , Inibidor da Ligação a Diazepam , Espectroscopia de Ressonância de Spin Eletrônica , Eletroforese em Gel de Poliacrilamida , Escherichia coli/genética , Genes Fúngicos , Genoma Fúngico , Humanos , Ponto Isoelétrico , Espectrometria de Massas , Dados de Sequência Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Saccharomyces/química , Saccharomyces/genética , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Alinhamento de SequênciaRESUMO
We have expressed a bovine synthetic acyl-CoA-binding protein (ACBP) gene in yeast (Saccharomyces cerevisiae) under the control of the GAL1 promoter. The heterologously expressed bovine ACBP constituted up to 6.4% of total cellular protein and the processing was identical with that of native bovine ACBP, i.e. the initiating methionine was removed and the following serine residue was N-acetylated. The expression of this protein did not affect the growth rate of the cells. Determination of the yeast acyl-CoA pool size showed a close positive correlation between the ACBP content of the cells and the size of the acyl-CoA pool. Thus ACBP can act as an intracellular acyl-CoA pool former. Possible physiological functions of ACBP in cells are discussed.
Assuntos
Acil Coenzima A/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Neoplasias , Animais , Sequência de Bases , Proteínas de Transporte/genética , Bovinos , Clonagem Molecular , Escherichia coli , Proteínas de Ligação a Ácido Graxo , Dados de Sequência Molecular , Oligonucleotídeos , Plasmídeos , Regiões Promotoras Genéticas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiaeRESUMO
A longitudinal investigation was undertaken to follow the nutritional status of 30 patients receiving chronic dialysis (19 patients in haemodialysis and 11 patients receiving continuous outpatient peritoneal dialysis) over a period of 14 months. A significant decrease in serum transferrin from 28 mumols/litre to 25 mumols/litre was registered (Pratt's test 0.01 less than p less than 0.05) while three other nutritional parameters (Relative Body Weight (RBW), Triceps Skin Fold (TSF) and Mid-Arm Muscle Circumference (MAMC)) did not alter significantly. Employment of a nutritional scoring system revealed that the incidence and degree of malnutrition were unchanged during the period concerned. It is concluded that conventional dialysis therapy with a relatively liberal diet does not appear to result in improvement in the nutritional status of the dialysis patients and that prevention of malnutrition in patients with chronic renal insufficiency must receive high priority.
