Cross-linking of membrane phospholipid and protein using putative monofunctional imidoesters

Abstract The reaction of methyl acetimidate or isethionyl acetimidate with mitoplasts at pH 8.5 yields two derivatives of phosphatidylathinolamine. These derivatives are shown to be the mono-amidine derivative and the bis-derivative of phosphatidylethanodamine. The bis-derivative represents one phosphatidylathinolamine cross-linked to another phosphatidylathinolamine. Similar derivatives are formed by the reaction of dipalmitoyl phosphatidylathinolamine with these imidoesters in organic reaction with the exception that much more monoderivative is primarily the mono-derivative. The bis-derivative was not detected. The reaction of bovine rod oester segment discs with methyl acetimidate causes cross-linking of 30% of the membrane rhodopsin as dimers. Putative monofunctional imidoesters cause considerable cross-linking of both phospholipids and protein in cell membranes. Crosslinking can be minimized at pH 9.0.