Quantitative NH₂ Terminal Evaluation of Elastin as A Measure of Polypeptide Integrity

Abstract

The quality of a given elastin preparation has been a matter of growing concern to those of us involved in isolating this fiber from complicated tissues such as the lung. Amino acid analysis is not a good index of quality. When we speak of quality we specifically refer to integrity of the polypeptide chains of the elastin which has been isolated. In this paper we wish to present a method that appears promising for the evaluation of such quality. It is a method which looks at the free NH₂ terminal amino acids in purified elastin, identifies and quantitates them in a relatively short period of time. The need for the method arose after we had applied various “non-degradative” techniques in isolating elastin from porcine lung. The analyses in all these preparations look very similar and yet we were quite certain that the integrity of the polypeptide chains varied considerably. We had specifically focused on a method described by Serafini-Fracassini, et al. (1), which involved the use of highly purified collagenase to rid the elastin of collagen contaminants.