Biosynthesis of human cystathionine beta-synthase in cultured fibroblasts.
A single specific radiolabeled polypeptide with an apparent Mr = 63,000 was recovered when cystathionine beta-synthase (EC 4.2.1.22) was precipitated from extracts of radiolabeled cultured human fibroblasts with an antiserum raised against pure human liver synthase, and the immunocomplexes were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Partial proteolysis of this fibroblast subunit and of the subunit of pure human liver synthase (Mr = 48,000) produced similar peptide patterns. Pulse-chase experiments, however, did not provide any evidence for post-translational modification of the fibroblast synthase subunit into a smaller "hepatic" form. Immunoprecipitation of polypeptides synthesized in vitro from human fibroblast mRNA revealed a polypeptide with the same mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as the synthase subunit found in whole cell extracts. We conclude that the Mr = 63,000 subunit is the primary translational product of the gene for cystathionine beta-synthase in human fibroblasts.
D002478:Cells, Cultured; D003541:Cystathionine beta-Synthase / Q000096:biosynthesis*; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D006836:Hydro-Lyases / Q000096:biosynthesis*; D046911:Macromolecular Substances; D008970:Molecular Weight; D012867:Skin / Q000201:enzymology*
D046911:Macromolecular Substances; D006836:Hydro-Lyases; D003541:Cystathionine beta-Synthase