Sulfur uptake by type I collagen from methyl mercaptan/dimethyl disulfide air mixtures

Type I acid-soluble collagen, suspended in 0.02 M Tris/0.13 M NaCl buffer (pH 7.4), was exposed to air atmosphere admixed with 10.7 X 10(-9) moles of [35S]-labeled dimethyl disulphide/methyl mercaptan mixture in the ratio of 99.82% (CH3S)2/0.18% CH3SH. Gas chromatographic analyses of head-space following one and four days of incubation indicated that all of the CH3SH was absorbed from the head-space by the collagen-containing liquid phase, while the (CH3S)2 concentration of the head-space remained essentially unchanged. Of the total [35S]-activity initially present in the head-space, only 1.0 the total [35S]-activity initially present in the head-space, only 1.0 and 1.86% was absorbed by the collagen-containing liquid phase within one and four days, respectively. Paper chromatographic separation of the reaction mixture showed that only 0.42 and 0.60% of the radioactivity in the head-space was associated with collagen after one and four days of reaction. In comparable [35S]-H2S systems devoid of (CH3S)2, all of the H2S was absorbed within 48 hours of incubation with 18.04% (1 day) and 18.28% (4 days) of the available [35S]-H2S complexed with collagen. The results provide evidence that the reaction of collagen with H2S and CH3SH/(CH3S)2 mixture proceeded via the H2S and CH3SH thiol groups.