{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T15:04:11Z","timestamp":1781103851891,"version":"3.54.1"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"14","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1984,7]]},"abstract":"<jats:p>A polypeptide-dependent protein kinase was purified about 80-fold from an extract of plasma membranes of Ehrlich ascites tumor cells. The membranes were extracted with Nonidet P-40, and the extract was purified by ammonium sulfate fractionation and hydroxylapatite and affinity chromatography. The activity was stimulated 10-fold or more by polypeptide preparations from a variety of tissues, including placenta and hypothalamus. Polypeptide-dependent protein kinase had a pH optimum of about 7.5 and required Mg2+ for activity. Mn2+ at low concentrations (200 microM) stimulated enzyme activity somewhat but inhibited activity strongly at higher concentrations. The best available substrate for polypeptide-dependent protein kinase was beta-casein, and little or no phosphorylation was observed with alpha-casein, kappa-casein, phosvitin, alpha-lactalbumin, alpha-lactoglobulin, and histone. However, several endogenous substrates from plasma membranes of Ehrlich ascites tumor cells were phosphorylated. Polypeptide-dependent protein kinase activity was not inhibited by 10 mM N-ethylmaleimide, and this resistance was useful in differentiating this protein kinase from other protein kinases that were present in crude fractions and sensitive to the inhibitor.<\/jats:p>","DOI":"10.1073\/pnas.81.14.4250","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T05:27:08Z","timestamp":1149053228000},"page":"4250-4254","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":4,"title":["New protein kinase from plasma membrane of Ehrlich ascites tumor cells activated by natural polypeptides."],"prefix":"10.1073","volume":"81","author":[{"given":"E","family":"Racker","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M","family":"Abdel-Ghany","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K","family":"Sherrill","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C","family":"Riegler","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"E A","family":"Blair","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1984,7]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.81.14.4250","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T12:03:07Z","timestamp":1649851387000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.81.14.4250"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1984,7]]},"references-count":0,"journal-issue":{"issue":"14","published-print":{"date-parts":[[1984,7]]}},"alternative-id":["10.1073\/pnas.81.14.4250"],"URL":"https:\/\/doi.org\/10.1073\/pnas.81.14.4250","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1984,7]]},"assertion":[{"value":"1984-07-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}