title: Purine nucleoside phosphorylase synthesis and turnover in human lymphoid cells.
abstract: We have studied the turnover and synthesis of purine nucleoside phosphorylase by using a polyclonal rabbit antiserum to this protein. The turnover of purine nucleoside phosphorylase was studied in the B lymphoblast cell, WI-L2, by specific immunoprecipitation of [3H]leucine-labeled proteins. The half-lives for total protein and purine nucleoside phosphorylase were 14.5 and 14.1 hr, respectively. For cells cultured in the presence of inosine the half-life of purine nucleoside phosphorylase was reduced to 11.2 hr. The synthesis of purine nucleoside phosphorylase was analyzed during phytohemagglutinin-stimulated T cell transformation by pulse labeling cells with [35S]methionine. Purine nucleoside phosphorylase synthesis increased greater than 10-fold during the first 12 hr of transformation and continued to a maximum of 30-fold. The relative rate of purine nucleoside phosphorylase labeled to total proteins was 0.04% in unstimulated T cells and increased to 0.18% 12 hr after stimulation. These studies identify some preferential synthesis of purine nucleoside phosphorylase during the early stages of T cell transformation.
mesh_terms: D001402:B-Lymphocytes / Q000378:metabolism; D002460:Cell Line; D006801:Humans; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism*; D010430:Pentosyltransferases / Q000378:metabolism*; D011683:Purine-Nucleoside Phosphorylase / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase