Radioactive sulfur studies. I. Synthesis of methionine.* II. Conversion of methionine sulfur to taurine sulfur in dogs and rats. III. Distribution of sulfur* in the proteins of animals fed sulfur* or methionine.* IV. Experiments in vitro with sulfur and hydrogen sulfide
Tarver, Harold; Schmidt, C.L.A.
Journal of Biological Chemistry 146(1): 69-84
ISSN/ISBN: 0021-9258 Accession: 025337161
In this paper an asterisk indicates that the substance contains traces of S35 (radioactive S). Dogs fed methionine*, a synthesis of which is described, excreted bile from which taurine* was isolated, indicating that the S of methionine was used in part for the synthesis of taurine. The internal organs of rats fed S* contained little radioactive S, hence the use of elementary S by the rat for the synthesis of S-containing amino acids is improbable. Proteins of dogs and rats contained a large part of the radioactive S fed as methionine*. The % replacement of S with radioactive S varied in different tissues, but the different protein fractions of liver and plasma showed the same % replacement. The evidence indicates that serum albumin is not a system of components that are common to the other serum proteins. The results support the idea that no distinction can be made between endogenous and exogenous metabolism. When cysteine was oxidized with S*, no radioactive S was found in the cystine formed. When cystine (or cysteine) was partly decomposed in alkaline soln. in the presence of H2S*, no radioactive S was present in the residual cystine (or cysteine).