title: Tricarboxylic acid-cycle enzymes and ATP pool in facultative and obligate methylotrophs: Pseudomonas J26 and Methylomonas Pl1.
abstract: 1. No essential differences were found in the activities of tricarboxylic acid-cycle enzymes in the newly isolated facultative methylotroph Pseudomonas J26 and obligate methylotroph Methylomonas Pl1. 2-Oxoglutarate dehydrogenase and succinate dehydrogenase were absent in Methylomonas Pl1; in Pseudomonas J26 the functioning of the cycle was imparied only on the methanol medium. Citrate synthase of both organisms showed low sensitivity to 2-oxoglutarate, NADH and ATP. 2. In both methylotrophs, methanol dehydrogenase was inhibited non-competitively by ATP: the activity was reduced by half by ATP at a concentration of 5 mM. 3. Concentration of ATP in the log-phase cultures of Methylomonas Pl1 was about twice as high as in Pseudomonas J26 (4.7 and 1.7 mumol/g dry wt., respectively). 4. Differences between the energy state of Methylomonas Pl1 and Pseudomonas J26 might be due to the higher ability of the former to oxidize methanol and/or lower energy requirement for C1 assimilation by the hexulose pathway in the obligate methylotroph.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000446:Aldehyde-Lyases / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D002952:Citric Acid Cycle; D004734:Energy Metabolism; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D006600:Hexosephosphates / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000378:metabolism; D007522:Isocitrate Lyase / Q000378:metabolism; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism; D008772:Methylococcaceae / Q000201:enzymology*; D011549:Pseudomonas / Q000201:enzymology*; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D006600:Hexosephosphates; D000255:Adenosine Triphosphate; D000429:Alcohol Oxidoreductases; D008291:Malate Dehydrogenase; D007521:Isocitrate Dehydrogenase; D007655:Ketoglutarate Dehydrogenase Complex; D013385:Succinate Dehydrogenase; D005969:Glutamate Dehydrogenase; D002950:Citrate (si)-Synthase; D000446:Aldehyde-Lyases; C021355:hexose phosphate synthetase; D007522:Isocitrate Lyase