Figure 3: Citrate biosynthesis and degradation.
From: Genome sequencing and analysis of the versatile cell factory Aspergillus niger CBS 513.88
The putative localization of enzymes and transporters is indicated. Their symbols are underlined when expression of their corresponding A. niger genes (under noncitric acid–producing conditions) was observed; the numbers are in bold in this legend. The numbers in parentheses next to the enzyme symbols indicate the number of genes found for a specific function whereas in the case of the pyruvate dehydrogenase complex they indicate the total number of genes involved in the complex. cPYC, cytoplasmic pyruvate carboxylase (An04g02090); cMDH, cytoplasmic malate dehydrogenase (An11g07190, An12g00160, An15g00070); cACO, cytoplasmic aconitase (An 02g11040, An09g03870); cIDH, NADP-specific isocitrate dehydrogenase (An02g12430; note that cytoplasmic or mitochondrial localization occurs by differential translational start point utilization); cACL, cytoplasmic ATP-citrate lyase (An11g00530); PYT, putative pyruvate carrier, not identified because of lack of characterization in other organisms; OAT, oxaloacetate transporter (An14g06860); CMC, citrate/malate carrier (An11g11230, An18g00070); PDH, pyruvate dehydrogenase complex E1-alpha subunit (An07g09530, An11g04550), E1-beta subunit (An01g00100), E2 dihydrolipoamide acetyltransferase (An07g02180), E3 lipoamide dehydrogenase (An07g06840), E3 binding protein (An02g11910); mPYC, mitochondrial pyruvate carboxylase (An15g02820); mMDH, mitochondrial malate dehydrogenase (An16g00120); mCL, mitochondrial citrate lyase (An01g08610); AK, acetate kinase (An02g06420) and ACS, acetyl-CoA synthase (An05g00390); CS, citrate synthase (An01g09940, An08g10920, An09g06680); mACL, mitochondrial ATP-citrate lyase (An11g00510); mACO, mitochondrial aconitase (An08g10530, An16g05760); mIDH, mitochondrial NADP- and NAD-isocitrate dehydrogenases (An02g12430, An08g05580, An18g06760).
