title: Free and membrane-bound ribosomes. VI. Distribution of free sulphydryl groups in rabbit reticulocyte ribosomes.
abstract: When free and membrane-bound ribosomes were titrated with N-ethyl[14C]-maleimide or 5,5'-dithio-bis(2-nitrobenzoic acid), 25 free SH groups were detected in  polysomes, 10 in the 60 S subunit and 14 in the 40 S subunits. When individual ribosomal proteins were analysed, one large subunit protein L14 was found to be strongly labelled compared to the other ribosomal proteins, in polysomes, monosomes and subunits. However, two additional protein spots from the small subunit were more radioactive in monosomes and subunits than inpolysomes. In all these studies, it was found that the distribution of free SH groups in free and membrane-bound ribosomes was identical except for the few proteins which were reported before to be specific for free or membrane-bound ribosomes (Fehlmann, ., Bellemare, G. and Godin, C. (1975) Biochim. Biophys. Acta 378, 119-124 and Fehlmann, M., Bellemare, G. and Godin, C. (1975) FEBS Lett. 59, 8-12).
mesh_terms: D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000648:ultrastructure; D004228:Dithionitrobenzoic Acid; D005033:Ethylmaleimide; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D012269:Ribosomal Proteins; D004228:Dithionitrobenzoic Acid; D005033:Ethylmaleimide