Pyruvate carboxylase PYC

Pyruvate carboxylase pyc Carboxylate pyruvate to form oxaloacetate... 

SA production in metabolically engineered Corynebacterium glutamicum AWh-pCRA717 strain under oxygen-deprived condition. Native pyruvate carboxylase (pyc) was overexpressed and lactate dehydrogenase [idh) was disrupted in this strain. X indicates knocked-out gene. Black line indicates overexpression. PEP, phosphoenolpyruvate OAA, oxaloacetate MAL, malate FUM, fumarate ... 

Peters-Wendisch PG, Kreutzer C, Kalinowski J, Patek M, Sahm H, Eukmamis BJ. (1998). Pyruvate carboxylase from Corynebacterium glutamicum characterization, expression and inactivation of the pyc gene. Micmbiology, 144, 915-927. 

For glutamate production, a balanced supply of acetyl-CoA and oxaloacetate is important to proceed TCA cycle reactions toward 2-oxoglutarate, because it is a substrate for glutamate biosynthesis catalyzed by GDH. In particular, anaplerotic reactions, which supply oxaloacetate from the glycolytic intermediates, are caudal. C. glutamicum possesses two enzymes for anaplerotic reactions phosphoenolpyru-vate carboxylase (PEPC) encoded by ppc and pyruvate carboxylase (PC) encoded by pyc (Bormann et al. 1992 Eikmanns et al. 1995 O Regan et al. 1989 Peters-Wendisch et al. 1998). PC requires biotin as a cofactor for its activity. MFA was conducted to understand the role of these anaplerotic reactions in glutamate production. 

PEP, phosphoenolpyruvate OAA, oxaloac-etate MAL, malate FUM, fumarate ICT, isocitrate CIT, citrate AcCoA, acetyl-CoA QOH, menaquinol GOX, glyoxylate aceA, isoci-tratelyase aceB, malate synthase pyc, pyruvate carboxylase ppc, phosphoenolpyruvate... 

AcCoA, acetyl-CoA pta, phosphate acetyl-transferase ackA, acetate kinase ppc, PEP carboxykinase mdh, malate dehydrogenase fum, fumarase frd, fumarate reductase pyc, pyruvate carboxylase and pykF, pyruvate kinase. This figure was redrawn based on [36]. With permission 2009 Federation of European Microbiological Societies published by Blackwell Publishing Ltd. 

Figure 17.9 Metabolic pathways involved in SA production in the metabolically engineered Escherichia coli (AFP111/pTrc99A-pyc) strain. Rhizobium etii pyruvate carboxylase was introduced into the engineered strain. Black lines indicate overexpression.

Figure 17.15 Major metabolic pathways involved in SA production in Saccbaromyces cerevisiae. Bold arrows indicate the major routes for succinate synthesis starting from glucose (a) via the reductive TCA cycle and (b) via the giyoxyiate cycle. PEP, phos-phoenolpyruvate OAA, oxaloacetate MAL, malate FUM, fumarate Suc-CoA, sucdnyl-CoA cr-KG, cr-ketoglutarate ICT, isodtrate CIT, citrate, ppc, PEP carboxykinase pyc, pyruvate carboxylase pyk, pyruvate kinase ...

Abbreviations NTP nucleotide triphosphate, PCK phosphoenolpyruvate carboxykinase, NDP nucleotide diphosphate, PEP phosphoenolpyruvate, PPC phosphoenolpyruvate carboxylase, OAA oxalacetic acid or oxalacetate and PYC pyruvate carboxylase... 

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