title: The borohydride-reducible compounds of human aortic elastin. Demonstration of a new cyclic amino acid in alkali hydrolysate, and changes with age and in patients with annulo-aortic ectasia including one with Marfan syndrome.
abstract: Human aortic elastin reduced with [3H]borohydride was analysed by ion-exchange chromatography after alkali or acid hydrolysis. Alkali hydrolysates of elastins contained a radioactive peak that was eluted between proline and leucine. This peak was not present in foetal elastin, but its proportion increased steadily during aging. Aortic samples from patients with annulo-aortic ectasia (aneurysm of the ascending aorta), including one with classical Marfan syndrome, contained less elastin (CNBr-insoluble material) than did the age-matched controls. The proportion of radioactivity in the new peak of all these aortas was low when compared with age-matched controls. Gas-chromatographic/mass-spectrometric analysis suggested that it contained a cyclic derivative of a hydrated aldol-condensation product. The concentration of the cross-link precursors, lysine aldehyde and aldol-condensation product (estimated from the acid-hydrolysis product 6-chloronorleucine and the acid-degradation product of reduced aldol-condensation product) was high in very young aortas but remained quite stable after childhood. No differences were observed in cross-link profiles of acid hydrolysates between pathological and control aortas. A low proportion of radioactivity in the new peak may indicate the presence of young or immature elastin in the pathological aortas.
mesh_terms: D000328:Adult; D000367:Age Factors; D000596:Amino Acids / Q000032:analysis*; D001011:Aorta / Q000032:analysis*; D001018:Aortic Diseases / Q000378:metabolism; D001894:Borohydrides; D002648:Child; D002852:Chromatography, Ion Exchange; D004108:Dilatation, Pathologic / Q000378:metabolism; D004549:Elastin; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006868:Hydrolysis; D008297:Male; D008382:Marfan Syndrome / Q000378:metabolism; D008875:Middle Aged
chemical_list: D000596:Amino Acids; D001894:Borohydrides; C025364:sodium borohydride; D004549:Elastin