Positive Schiff Reactivity of Aortic Elastin Without Prior HIO₄ Oxidation; Influence of Maturity and A Suggested Source of the Aldheyde

Abstract

Rat aortic elastin contains a non-periodic acid-engendered aldehyde that reacts with either conventional pH 2.5 Schiff's reagent or a Schiff's reagent of pH 6.7. The elastin of animals 20 and 40 days old was colored a vivid purple-red, whereas the elastin from 18-mo-old animals was not stained. Elastin from the young animals when subjected to aldehyde blockage prior to HIO₄ oxidation was not stained. Histochemical and biochemical literature of the past 10 yr pertinent to Schiff and periodic acid-Schiff reactivity with elastin indicate that an intermediate compound, α-amino adipic-δ-semialdehyde, formed during the conversion of lysin to one of several cross linking amino acids found in elastin, is the source of the aldehyde responsible for the direct Schiff reaction.