Biochemistry, Department of


Date of this Version



The Journal of Biological Chemistry, Vol. 248, No.7, Issue of April 10, pp. 2317- 2322, 1973


Used by permission


The effects of acyl-CoA derivatives (C8 to C20) on the activity

of the fatty acid synthetases from yeast and Corynebacterium

diphtheriae have been examined. Both enzyme

systems are inhibited by the longer chain acyl thioesters

(C16 to C20) and protected against this inhibition by bovine

serum albumin (BSA). Identical relief from acyl-CoA inhibition

is provided by the 6-0-methylglucose-containing

lipopolysaccharide (MGLP), from Mycobacterium phlei. It

is shown that MGLP forms a stable complex with palmitylCoA.

This interaction accounts for the BSA-like effects of

the polysaccharide. BSA and MGLP have two further effects

on the fatty acid synthetases under study, also attributable

to complex formation with palmityl-CoA. They

stimulate the rate of over-all synthesis from acetyl-CoA and

malonyl-CoAt and they cause a shift of the fatty acid pattern

towards products of shorter chain length. The observed effects

are discussed in terms of the regulation of fatty acid

synthesis both with respect to rate and product composition.

It is concluded that in the two microbial enzyme systems negative

feedback inhibition and its relief are important control