Kinetic Studies With Transglutaminases

The study investigated the transfer reaction of [14C]methylamine into the acetylated B chain of oxidized insulin catalyzed by various transglutaminases at pH 7.5 with calcium ions. The reaction consistently produced peptide-bound γ-glutamic acid methylamide, supporting a ping-pong mechanism for human plasma and guinea pig hair follicle transglutaminases, similar to that proposed for guinea pig liver transglutaminase. The study also found that calcium activation of plasma transglutaminase follows an equilibrium-ordered mechanism, and the kinetic similarities between human plasma and platelet transglutaminases suggest closely related catalytic subunits. Additionally, improved purification methods for plasma and platelet protransglutaminases were presented.