Lipid Ddpendence of Diacylglyderol Kinase from Escherichia coli

Abstract

Diacylglycerolkinase apoprotein was purified from membranes of Encherichia coli K 12. The protein was catalytically inactive, but regained activity upon recombinatin with phospholipids, certain neutral llipids, of fatty acids. Activation proceded with positive cooperativity and was independent of the exact chemical structure, bilayer arrangement or electrical charge of the lipid. The apoprotein was activated by lysophosphatidylethanolamine but not by lysohosphatidylcholone. 1‐Monooleoylglycerol was an effective activator and substrats at the same time. The fluidity and the polatity o flipids appeared to be generally imjportent for activation. Lipid polatity was estimated by a triaclyglyderl/phosphatidylcholohn‐partitioning procedure. All lipids showing preferential association with triaclglycerol failed to activate the kinase apopretein even in the presence of detergent. It is concluded that a defined hydrophilic/lipophilic balance of the lipid was required for the formation of a functinal lipoprotein complex. Copyright © 1983, Wiley Blackwell. All rights reserved