Substrate activity of phosphonic acid analogues of CDPdiglyceride in the synthesis of phosphoglycerides in Escherichia coli.
Two phosphonic acid analogues of CDPdiglyceride, D L-2-hexadecoxy-3-octadecoxypropylphosphonyl-O-(cytidine 5'-phosphate) (analogue (I), and D L-3,4-dioctadecoxybutylphosphonyl-O-(cytidine 5'-phosphate) (analogue (II), have been synthesized and examined as substrates for the enzymes involved in the synthesis of phosphoglycerides in Escherichia coli. Both compounds were substrates for CDPdiglyceride:sn-glycerol-3-phosphate phosphatidyl transferase. The analogues had similar Km values (Km of 0.060 mM for analogue (II): Km of 0.080 mM for analogue (I) and a V identical to that of CDPdipalmitin (Km of 0.044 mM). In contrast, the analogues were poor substrates for CDPdiglyceride:L-serine phosphatidyl transferase. The analogues had lower Km values (Km of 0.40 mM for analogue (II); Km of 0.80 mM for analogue (I) than CDPdipalmitin (Km of 1.4 mM). The V, although identical for both analogues, was ten-fold lower than that observed with the natural substrate. An analysis of the products of these enzymatic reactions suggests that phosphatidylglycerophosphate phosphatase and phosphatidylserine decarboxylase may also possess a certain degree of substrate specificity.
D002855:Chromatography, Thin Layer; D003567:Cytidine Diphosphate Diglycerides / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D007700:Kinetics; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D063065:Organophosphonates; D010743:Phospholipids / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism; D013329:Structure-Activity Relationship
D003567:Cytidine Diphosphate Diglycerides; D009702:Nucleoside Diphosphate Sugars; D063065:Organophosphonates; D010743:Phospholipids; D010770:Phosphotransferases