Type‐I Trimer and Type‐I Collagen in Neutral‐Salt‐Soluble Lathyritic‐Rat Dentine

Abstract
Triple-helical collagen molecules were obtained from EDTA-demineralized lathyritic rat incisors by neutral buffer extraction. Component .alpha. chains, isolated by sequential ion-exchange and gel-filtration chromatography, were shown to be .alpha.1I and .alpha.2 chains by cyanogen bromide peptide analysis. The .alpha.1I:.alpha.2 chain ratio was approximately 3:1, which is greater than expected for type I collagen. The excess of .alpha.1I chains over that required for type I collagen was due to the presence of type I trimer molecules. Fractional salt precipitation separated type I collagen from type I trimer. It is not known at present if type I trimer synthesis also occurs in normal rat tissues.