Wr. Mann et al., KINETIC, CIRCULAR-DICHROISM AND FLUORESCENCE STUDIES ON HETEROLOGOUSLY EXPRESSED CARNITINE PALMITOYLTRANSFERASE-II, Journal of enzyme inhibition, 9(4), 1995, pp. 303-308
K-m estimates for carnitine and palmitoyl-CoA of heterologously expres
sed rat liver carnitine palmitoyltransferase-II (rCPT-II) were 950+/-2
7 mu M and 34+/-6 mu M, respectively. V-max for the enzyme was 1.8 mu
mol/min/mg purified protein. Consistent with an ordered reaction mecha
nism in which palmitoyl-CoA binds first, SDZ CPI 975, a reversible car
nitine palmitoyltransferase inhibitor containing both carnitine and al
kyl moieties, inhibited rCPT-II competitively with carnitine and uncom
petitively with palmitoyl-CoA. Substrate-enzyme interactions were exam
ined by circular dichroism (CD) and fluorescence. Both carnitine and p
almitoyl-CoA alone induced conformational changes in the enzyme; disso
ciation constant estimates by CD for carnitine and palmitoyl-CoA were
41+/-5 mu M and 7+/-2 mu M, respectively.