Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:5.4.2.8 (phosphomannomutase)
 238 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alginate synthesis by the highly mucoid Pseudomonas aeruginosa 8821 M is growth-phase-dependent, and the alginate produced per unit of biomass reaches maximum values in the deceleration phase of growth. However, the degree of polymerization increases as batch growth proceeds, reaching maximum values at the stationary phase of growth. The activity of the four enzymes leading to GDP-mannuronic acid formation, phosphomannose isomerase, phosphomannomutase, GDP-mannose pyrophosphorylase and GDP-mannose dehydrogenase peaked earlier at the late exponential phase. Growth-phase-dependent activity of alginate biosynthetic enzymes correlates with the level of transcription of the encoding alginate genes algA, algC and algD during growth, as indicated by Northern blot hybridization experiments. The pattern of coordinate transcriptional growth-phase regulation of these alginate structural genes concurs with the growth-dependent transcription of the regulatory gene algR1.
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PMID:Growth-phase-dependent alginate synthesis, activity of biosynthetic enzymes and transcription of alginate genes in Pseudomonas aeruginosa. 777 78

Alginate production by the highly alginate-producing Pseudomonas aeruginosa 8821M was maximal at a dissolved oxygen tension (DOT) of 5% of air saturation. Lower DOT limited growth and alginate synthesis. At higher DOT values up to 70% of air saturation, the specific alginate production rate decreased. Nevertheless, the molecular mass of the alginate increased at higher aerations, as indicated by the viscosity of solutions of the isolated biopolymer. The specific activity of the four enzymes leading to GDP-mannuronic acid formation, phosphomannose isomerase (PMI), phosphomannomutase (PMM), GDP-mannose pyrophosphorylase (GMP) and GDP-mannose dehydrogenase (GMD), increased with DOT of up to 25%. At higher DOT, however, only GMP and GMD maintained their maximum values. Changes observed at high oxygen concentrations in the relative activities of PMI and GMP, which are activities of the same bifunctional protein, were attributed to the much higher sensitivity of PMI activity to irreversible oxidative inactivation. The less pronounced decrease of PMM activity at high DOT correlated with an intermediate sensitivity to oxidative inactivation, but could also be related to sequential induction of PMM by the product of the PMI reaction. Thus, oxygen-dependence of alginate synthesis was at least partially the effect of DOT on GDP-mannuronic acid formation. Optimal aerations for maximal alginate production (DOT = 5-10%) were below the aeration level (70%) that led to the highest viscosity. These results suggest that, like GMD, polymerization activity is not very sensitive to oxidative inactivation and they are consistent with the hypothesis that polymerization is dependent on GMD activity, or is regulated in a similar way.
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PMID:Oxygen-dependent alginate synthesis and enzymes in Pseudomonas aeruginosa. 838 19