Journal of Lipid Research, Vol 26, 1151-1159, Copyright © 1985 by Lipid Research, Inc.
Inhibition of liver prenyltransferase by citronellyl and geranyl phosphonate and phosphonylphosphate
G Popjak and C Hadley
Citronellyl- and geranylphosphonic acids and the corresponding
phosphonylphosphates were made and tested as inhibitors of liver
prenyltransferase. Kinetic analysis showed that citronellyl- and
geranylphosphonylphosphate were powerful inhibitors of the enzyme, and that
they were competitive inhibitors with geranyl diphosphate and
noncompetitive inhibitors with isopentenyl diphosphate. Two inhibition
constants, representing the equilibria [E][I]/[EI] = K5 and [ES1][I]/[ES1I]
= K9, have been defined for the inhibitors. For
citronellylphosphonylphosphate, the value of K5 was 1.25 microM and K9 was
3.30 microM; for geranylphosphonylphosphate, K5 = 1.50 microM and K9 = 1.60
microM. The phosphonates were very poor linear mixed noncompetitive
inhibitors with respect to both substrates of the transferase.