Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.2.13 (aldolase)
 3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

4-Hydroxy-4-methyl-2-oxoglutarate aldolase [4-hydroxy-4-methyl-2-oxoglutarate pyruvate-lyase: EC 4.1.3.17] has been purified to homogeneity (about 770-fold purification, yield 11.4%) from Pseudomonas ochraceae grown on phthalate. The enzyme has a molecular weight of 160,000 (gel filtration on Bio-Gel A-1.5m), a subunit molecular weight of 26,000 (SDS-PAGE) and an isoelectric point of 5.0 (isoelectric focusing). The enzyme requires divalent metal ions such as Mg2+, Mn2+, Co2+, Zn2+, and Cd2+ for activity. The enzyme actively cleaves 4-carboxy-4-hydroxy-2-oxoadipate, a physiological substrate of the enzyme, to give pyruvate and oxaloacetate, but shows much lower affinity for 4-hydroxy-4-methyl-2-oxoglutarate. 4-Hydroxy-2-oxoglutarate is cleaved at a low rate to pyruvate and glyoxylate. The l-isomers of the substrates are preferentially cleaved rather than the d-isomers as determined polarimetrically. The enzyme reactions are reversible: the equilibrium constants (pH 8.0, 25 C) for the HMG and HG cleavage reactions are about 0.07 and 0.03 M, respectively, whereas no equilibrium is observed with CHA due to oxaloacetate beta-decarboxylase activity associated with the enzyme. The enzyme activity is hardly affected by thiols and thiol reagents. The non-enzymatic cleavage reaction caused by various metal ions has also been studied to examine the mechanistic similarity to the enzymatic reaction.
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PMID:Purification and properties of 4-hydroxy-4-methyl-2-oxoglutarate aldolase from Pseudomonas ochraceae grown on phthalate. 222 32

The influence of a daily oral dose of alpha-ketoglutarate (AKG, 0.1 g/kg body weight), an intermediate metabolite in the Krebs cycle and a dietary additive, on the pituitary proteome of gilthead sea bream was determined by two-dimensional electrophoresis (2-DE). A high-resolution map of the sea bream pituitary proteome was generated. Proteins with a modified expression between Controls and AKG treated fish were further analysed by MALDI-TOF/TOF-MS and liquid chromatography combined with a nanoelectrospray (LC-MS/MS). The main changes in the proteome induced by AKG treatment were grouped. Metabolic proteins up-regulated with AKG supplementation included fructose-bis-phosphate aldolase, glyceraldehyde-phosphate dehydrogenase and malate dehydrogenase, all related to glucose metabolism (p<0.000). Protein folding related up-regulation with AKG supplementation included two isoforms of heat shock proteins as well as cyclophylin and chaperonin (p<0.000). An unexpected form of apolipoprotein-A-1 with lower molecular weight (15-16 kDa) was evidenced as being highly abundant in the pituitary proteome of Controls, yet it was down-regulated by AKG treatment. Finally, proteins found to be associated with regeneration of neural function namely cofilin and Vat-protein were up-regulated after AKG supplementation. The only hormone to be modified by AKG treatment was somatolactin, which was significantly down-regulated cf. Controls. In summary, these results provide evidence of a potential endocrine/metabolic regulatory loop activated by AKG supplementation.
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PMID:Dietary keto-acid feed-back on pituitary activity in gilthead sea bream: effects of oral doses of AKG. A proteomic approach. 2085 Nov 21