Impairment of collagen and elasin crosslinking by an amine oxidase inhibitor.

Abstract

SummaryTendons of chicks fed 0.1% iproniazid (IPN) contained twice as much 1 M NaCl- and 0.5 M acetic acid-extractable collagen as tendons from pair-fed controls. The concentration of elastin in aortas was reduced. Iproniazid fed to chicks inhibited the amine oxidase activity in homogenates of liver, heart, and aorta. Addition of pyridoxal phosphate to homogenates from both control and IPN-fed chicks enhanced the activity of amine oxidase in aorta to a greater extent than that of other tissues. Iproniazid decreased the oxidation of peptidyl lysine in elastin isolated from aortas grown in organ culture. In vitro inhibition of the aortic enzyme by IPN was competitively reversed by pyridoxal phosphate. These data support the hypothesis that an amine oxidase found in connective tissue and requiring pyridoxal phosphate is an important enzyme in the maturation of collagen and elastin.