Monogalactosyldiacylglycerol biosynthesis by direct acyl transfer in Anabaena variabilis. [Anabaena variabilis]

Conference · Fri May 01 00:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6078587

Chen, H H; Wickrema, A; Jaworski, J

The authors previously reported the direct acylation of monogalactosyldiacylglycerol (MGDG) by an enzyme in the membranes of the cyanobacterium (Anabaena variabilis. The enzyme requires acyl-acyl carrier protein (acyl-ACP) as substrate, but had no other additional cofactor requirements. Palmitoyl-, stearoyl- and oleoyl-ACP were all effective substrates. The A. variabilis membranes also had a hydrolase activity which metabolized the acyl-ACP to yield free fatty acid and ACP. Possible mechanisms for the acylation reaction include either acyl exchange with existing MGDG or direct acyl transfer to a lyso-MGDG, with concomitant release of free ACP. The mechanism of this reaction has been resolved using a double labelled (/sup 14/C)acyl-(/sup 14/C)ACP substrate prepared with E. coli acyl-ACP synthetase. Following incubation with the enzyme, the unreacted (/sup 14/C)acyl-(/sup 14/C)ACP was isolated and the (/sup 14/C)acyl/(/sup 14/C)ACP ratio determined. Comparison of this ratio to that of the original substrate indicated no change and eliminated acyl exchange as a possible mechanism. Therefore, the direct acylation of lyso-MGDG is the proposed mechanism for this enzyme. The reaction is apparently specific for MGDG synthesis, as other glycolipids and phospholipids were not labelled during incubations.

• Research Organization: Miami Univ., Oxford, OH
• OSTI ID: 6078587
• Report Number(s): CONF-870644-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550701 -- Microbiology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACYLATION
BACTERIA
BIOCHEMICAL REACTION KINETICS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
CYANOBACTERIA
DOUBLE LABELLING
ENZYME INDUCTION
ESCHERICHIA COLI
GENE REGULATION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LABELLING
LIPIDS
MEMBRANES
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
REACTION KINETICS
SUBSTRATES
TRACER TECHNIQUES