Polymerization of a Quinone-Crosslinked Marine Bioadhesive.

摘要

This research has had two main objectives: 1) to survey the biochemical diversity of DOPA-containing marine adhesive proteins and cements, and 2) to examine the chemical mechanism of quinone-tanning i.e. cross linking of DOPA-containing proteins. Studies conducted over the past year on Dihydoxyphenylalanine (DOPA)-containing proteins from G. demissa and M. edulis suggest that these form soluble, stable complexes with type II collagen, essentially shielding the latter from digestion by clostridial collagenase. No such shielding was conferred by the Fasciola DOPA-proteins. Catecholoxidase-catalyzed oxidation of the DOPA residues to o-quinones results in a substantial tautomerizationof the quinones to alpha, beta-dehydro DOPA. The rate of tautomerization at physiological pH is comparable to the proposed Michael addition of lysyl epsilon amino groups to quinones. This may suggest that alpha, beta-dehydro DOPA is an important intermediate in quinone-tanning. A new histidine-rich DOPA-containing egg shell precursor has been characterized from Fasciola hepatica. (AW)