Human fetal liver fatty acid binding proteins. Role on glucose-6-phosphate dehydrogenase activity.
Fatty acid binding proteins (FABPs) may play an important role in the transport and metabolism of fatty acids during human embryogenesis. Three fractions of FABP, namely, DE-I, DE-II and DE-III, having Mr 14,200 Da each and pI values 7.8, 6.9 and 5.4, respectively, have been detected in human fetal liver. These proteins were purified by heat and butanol precipitation of fetal liver supernatant as well as by gel filtration and ion-exchange chromatography. Fetal liver FABPs are immunochemically identical to each other. Concentrations of DE-I, DE-II and DE-III increase gradually from early gestation to term. DE-I is almost lipid-free, DE-II binds long-chain fatty acids nonspecifically and DE-III transports mainly arachidonic acid. DE-II and DE-III protect glucose-6-phosphate dehydrogenase, which furnishes NADPH for fatty acid synthesis, from the feed-back inhibition exerted by added palmitoyl-CoA and oleate. In the absence of exogenous inhibitors, this enzyme is stimulated by FABPs. DE-I has no effect on such inhibition. Thus, FABPs play a regulatory role in critical aspects of cellular physiology during human embryogenesis.
Das
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Department of Biochemistry, University College of Science, Calcutta, India.
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Mukherjea
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D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism; D005333:Fetus / Q000378:metabolism*; D005865:Gestational Age; D005954:Glucosephosphate Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D005779:Immunodiffusion; D007526:Isoelectric Point; D008099:Liver / Q000196:embryology / Q000378:metabolism*; D008970:Molecular Weight; D009249:NADP / Q000378:metabolism; D009363:Neoplasm Proteins; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D010171:Palmitoyl Coenzyme A / Q000494:pharmacology; D025521:Tumor Suppressor Proteins
D002352:Carrier Proteins; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D009363:Neoplasm Proteins; D009829:Oleic Acids; D025521:Tumor Suppressor Proteins; D010171:Palmitoyl Coenzyme A; D019301:Oleic Acid; D009249:NADP; D005954:Glucosephosphate Dehydrogenase