INVITRO INHIBITION OF COLLAGEN CROSS LINKS BY CATECHOL ANALOGS

[摘要] Catechol analogs inhibited the formation of hydroxylysine-derived intermolecular collagen cross links in tissue cultures of chick embryo calvaria. Formation of intermolecular collagen cross links was measured following incorporation of [14C]lysine, reduction with sodium borohydride and elution from an ion exchange column with a pyridine-formate gradient. Cultures grown in the presence of 10-3 M catechol, 10-3 M dopamine, 10-3 M L-dopa, or 10-3 M D,L-serine-(2,3,4-trihydroxybenzyl)-hydrazide demonstrated between 43-84% inhibition of hydroxylysine formation. Collagen biosynthesis was not diminished in these cultures as compared to controls without additions or with .beta.-aminopropionitrile when measured by collagenase digestion. The formation of hydroxylysine-derived intermolecular cross links was inhibited 34-93% for 5,5''-dihydroxylysinonorleucine and 7-71% for 5-hydroxylysinonorleucine. The catechol analogs inhibited lysyl hydroxylase activity as measured by specific 3H release as tritiated water from an L-[4,5-3H]lysine-labeled unhydroxylated collagen substrate prepared from chick calvaria. Since catechol analogs inhibit the formation of hydroxylysine in a cell-free assay; these compounds must pass into the cells of calvaria in this culture system to inhibit intracellular hydroxylysine formation and subsequently to diminish the reducible intermolecular cross links of the newly synthesized collagen.