Collagen heterogeneity in pig heart valves.

For the first time, it has been possible to solubilize a significant amount of heart valve collagen from 6 month old pigs by pepsin treatment. Chromatographic and electrophoretic analysis of this pepsin-soluble collagen gives evidence for the presence of two types of collagen molecules: type I collagen and another type which has properties similar to those of type III collagen. For example, this collagen, present as a gamma component, gives rise, when reduced by dithiothreitol, to two bands by SDS-acrylamide gel electrophoresis: a beta band and an alpha band. Furthermore, the collagenic web of this tissue is highly polymerized, which explains the inability to solubilize all of the collagen molecules and the presence of high-molecular-weight molecules in the pepsin-soluble fractions.