Peculiarities of glucose and glycerol metabolism in Nocardia vaccinii IMB B-7405

Abstract

It has been established that in cells of Nocardia vaccinii IMB B-7405 (surfactant producer) glucose catabolism is performed through pentose phosphate cycle as well as through gluconate (activi­ty of NAD+-dependent glucose-6- phosphate dehydrogenase and FAD+-dependent glucose dehydrogenase 835 ± 41 and 698 ± 35 nmol∙min-1∙mg-1 of protein respectively). 6-Phosphogluconate formed in the gluconokinase reaction is involved in the pentose phosphate cycle (activity of constitutive NADP+-dependent 6-phosphogluconate dehydrogenase 357 ± 17 nmol∙min-1∙mg-1 of protein). Glyce­rol catabolism to dihydroxyacetonephosphate (the intermediate of glycolysis) may be performed in two ways: through glycerol-3-phosphate (glycerol kinase activity 244 ± 12 nmol∙min-1∙mg-1 of protein) and through dihydroxyacetone. Replenishment of the C4-dicarboxylic acids pool in N. vaccinii IMV B-7405 grown on glucose and glycerol occurs in the phosphoenolpyruvate(PEP)carboxylase reaction (714–803 nmol∙min-1∙mg-1 of protein). 2-Oxoglutara­te was involved in tricarboxylic acid cycle by alternate pathway with the participation of 2-oxoglutarate synthase. The observed activity of both key enzymes of gluconeogenesis (PEP- carboxykinase and PEP-synthase), trehalose phosphate synthase and NADP+-dependent glutamate dehydrogenase confirmed the ability of IMV B-7405 strain to the synthesis of surface active glyco- and aminolipids, respectively.

Keywords

• activity of enzymes
• anaplerotic reactions
• biosynthesis
• catabolism of glucose and glycerol
• key enzymes
• Nocardia vaccinii IMB B-7405