Biosynthesis of the α Chains of Collagen Studied by Pulse-labeling in Culture

Cyanogen bromide cleavage of guinea pig skin collagen. Isolation and characterization of peptides from the α1 and α2 chains

“…c Values calculated for a molecular weight of 93,000 and an average residue weight of 91.4.d Includes homoserine lactone.« As methionine. molecular weights different from those obtained with digests of al from other species (compare Figure 1 with Figure 2 of Vuust and Piez (1970)). There was no peptide in the 18,000 molecular weight range (al-CB6), but a large peak preceded the 24,000 molecular weight range This peptide had a molecular weight of 43,000 (Table II) and could be purified on a 1.5 X 8 cm CM-cellulose column equilibrated with 0.04 m sodium acetate (pH 4.8) using a linear gradient of NaCl from 0 to 0.4 m over a total volume of 300 ml (chromatogram not shown).…”

“…These findings suggest that conversion of methionine to homoserine occurred without concomitant cleavage of the methionyl peptide bond. A similar uncleaved peptide has been isolated from chick (Lane and Miller, 1969;Igarashi et al, 1970), rat (Vuust et al, 1970), human (Click and Bornstein, 1970; 4: Molecular sieve chromatography (Sephadex G-75) of the product of CNBr digestion of 50 mg of GPSC al chain. A 1.8 X 90 cm column was equilibrated with 0.03 m ammonium propionate (pH 4.5).…”