Metabolism of L-glyceraldehyde 3-phosphate in Escherichia coli
When either /sup 3/H-labeled L-glyceraldehyde or /sup 3/H-labeled L-glyceraldehyde 3-phosphate (GAP) was added to cultures of Escherichia coli, the phosphoglycerides were labeled. More than 81% of the label appeared in the backbone of the phosphoglycerides. Chromatographic analyses of the labeled phosphoglycerides revealed that the label was normally distributed into phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. These results suggest that L-glyceraldehyde is phosphorylated and the resultant L-GAP is converted into sn-glycerol 3-phosphate (G3P) before being incorporated into the bacterial phosphoglycerides. Cell-free bacterial extracts catalyzed an NADPH-dependent reduction of L-GAP to sn-G3P. The partially purified enzyme was specific for L-GAP and recognized neither D-GAP nor dihydroxyacetone phosphate as a substrate. NADH could not replace NADPH as a coenzyme. The L-GAP:NADPH oxidoreductase had an apparent K/sub m/ of 28 and 35 ..mu..M for L-GAP and NADPH, respectively. The enzyme was insensitive to sulfhydryl reagents and had a pH optimum of approximately 6.6. The phosphonic acid analog of GAP, 3-hydroxy-4-oxobutyl-1-phosphonate, was a substrate for the reductase, with an apparent K/sub m/ of 280 ..mu..M.
- Research Organization:
- City Univ. of New York, Flushing
- OSTI ID:
- 6408841
- Journal Information:
- J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 169:6; ISSN JOBAA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
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CHROMATOGRAPHY
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ESCHERICHIA COLI
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