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)

Chemostat cultures of Erwinia amylovora 595, grown in mineral salts-nicotinic acid medium at 30 degrees C, and limited by D-glucose concentrations in the presence of dissolved oxygen tensions (D.O.T.) greater than about 6mm Hg, became limited by oxygen availability below about 4 mm Hg. This latter limitation was accompanied by a marked increase in acid production as the D.O.T. was depressed. The transition between D-glucose- and oxygen-limitation was also characterized by a maximum in succinate oxidase activity, and a minimum in the in situ respiration. D-Glyceraldehyde-3-phosphate dehydrogenase and D-fructose-1, 6-diphosphate aldolase showed small reductions in specific activity in the region 4-6 mm Hg D.O.T., but further reduction to 2 mm Hg resulted in a marked increase in the specific activity of aldolase. Malate dehydrogenase followed the converse trend, and attained very low activity levels when the D.O.T. decreased beyond the lower limits of detection. The in situ respiration was maximal at 2 mm Hg D.O.T., while potential respiration values were minimal at 2 mm Hg, and maximal at about 8 mm Hg D.O.T. The insitu respiration rate was proportional to dilution rate (D), in presence of excess oxygen, up to 0.18 h-1, after which a marked diminution occurred and continued until the wash-out rate was attained. Succinate oxidase activity decreased with increase in dilution rate, but remained constant above D equals 0.18 h-1. Malate dehydrogenase showed a persistent decline with increase in dilution rate, while D-glyceraldehyde-3-phosphate activity increased somehwat at higher dilution rates. The data are interpreted in terms of two transition points, at 6 and 2 mm Hg D.O.T., and of a change from respiratory to fermentative metabolism at low D.O.T., and at high dilution rates.
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PMID:Variation in the activity levels of selected enzymes of Erwinia amylovora 595 in response to changes in dissolved oxygen tension and growth rate of D-glucose-limited chemostat cultures. 111 45

Vitamin B(6)-dependent enzymes may be grouped into five evolutionarily unrelated families, each having a different fold. Within fold type I enzymes, L-threonine aldolase (L-TA) and fungal alanine racemase (AlaRac) belong to a subgroup of structurally and mechanistically closely related proteins, which specialised during evolution to perform different functions. In a previous study, a comparison of the catalytic properties and active site structures of these enzymes suggested that they have a catalytic apparatus with the same basic features. Recently, recombinant D-threonine aldolases (D-TAs) from two bacterial organisms have been characterised, their predicted amino acid sequences showing no significant similarities to any of the known B(6) enzymes. In the present work, a comparative structural analysis suggests that D-TA has an alpha/beta barrel fold and therefore is a fold type III B(6) enzyme, as eukaryotic ornithine decarboxylase (ODC) and bacterial AlaRac. The presence of both TA and AlaRac in two distinct evolutionary unrelated families represents a novel and interesting example of convergent evolution. The independent emergence of the same catalytic properties in families characterised by completely different folds may have not been determined by chance, but by the similar structural features required to catalyse pyridoxal phosphate-dependent aldolase and racemase reactions.
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PMID:Threonine aldolase and alanine racemase: novel examples of convergent evolution in the superfamily of vitamin B6-dependent enzymes. 1268 35

Poplar are important forestry species in China, but the Botryosphaeria dothidea pathogen causes serious economic losses worldwide. To identify candidate B. dothidea resistance proteins and explore the molecular mechanisms involved in poplar-pathogen interactions, proteomic responses of stem samples from resistant and susceptible poplar ecotypes to B. dothidea were investigated using nanoflow liquid chromatography-tandem mass spectrometry with label-free quantitative analysis. We identified 588 proteins, divided into 21 biological process categories including 48 oxidoreductases, 72 hydrolytic enzymes, 80 metabolic enzymes, and 29 proteins of unknown function. Differential proteome analysis revealed large differences between resistant Populus tomentosa Carr and susceptible Populus beijingensis Hsu ecotypes before and after inoculation. Among 102 identified proteins, 22 were highly upregulated in the resistant genotype but downregulated in the susceptible genotype. Proteins induced in P. tomentosa Carr in response to B. dothidea are associated with plant defenses including oxidoreductase activity (catalase, isocitrate dehydrogenase, and superoxide dismutase), phenylpropanoid biosynthesis and phenylalanine metabolism (alcohol dehydrogenase), photosynthesis (ATP synthase subunit alpha, ATP synthase gamma chain, photosystem I P700 chlorophyll a apoprotein A2, photosystem II CP47 chlorophyll apoprotein), carbon fixation (pyruvate kinase, triosephosphate isomerase, malic enzyme, phosphoglycerate kinase, ribulose-1,5-bisphosphate carboxylase, and ribulose bisphosphate carboxylase small chain), and glycolysis/gluconeogenesis (fructose-bisphosphate aldolase). Kyoto Encyclopedia of Genes and Genomes pathway analysis identified 168 proteins related to metabolic pathways, 41 proteins related to the biosynthesis of phenylpropanoids, and 36 proteins related to the biosynthesis of plant hormones, the biosynthesis of alkaloids derived from ornithine, lysine, and nicotinic acid, and photosynthesis in response to B. dothidea. Our findings provide insight into plant-pathogen interactions in resistant and susceptible poplar ecotypes infected with B. dothidea and could assist the development of novel strategies for fighting poplar canker disease.
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PMID:Comparative Proteomic Analysis of Plant-Pathogen Interactions in Resistant and Susceptible Poplar Ecotypes Infected with Botryosphaeria dothidea. 3136 64