{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T17:19:46Z","timestamp":1790702386399,"version":"4.1.0"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"18","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1982,9]]},"abstract":"<jats:p>The site of synthesis of alpha 2-plasmin inhibitor (alpha 2-PI), a physiologic inhibitor of plasmin, is not known with certainty. We have studied the production and secretion of alpha 2-PI by three established human liver cell lines derived from hepatocellular carcinoma and hepatoblastoma (Hep G2, Hep 3B, and PLC\/PRF\/5). As measured by a specific radioimmunoassay, the titer of alpha 2-PI increased in the medium of Hep G2 and Hep 3B cells with time, but no significant amount of alpha 2-PI was found in the medium of PLC\/PRF\/5. There was no evidence for a significant intracellular pool of this protein. On immunodiffusion against anti-alpha 2-PI serum, alpha 2-PI secreted by Hep G2 (G2 alpha 2-PI) formed a simple precipitin line of complete identity with the alpha 2-PI present in plasma (plasma alpha 2-PI). G2 alpha 2-PI behaved similarly to plasma alpha 2-PI in Sephadex G-150 gel filtration, sucrose density-gradient centrifugation, and crossed immunoelectrophoresis. G2 alpha 2-PI inhibited plasmin activity instantaneously in a functional assay and formed a complex with plasmin demonstrable by crossed immunoelectrophoresis. De novo synthesis of alpha 2-PI was shown by the presence of specific immunoprecipitable radioactivity in the medium after 5 hr of labeling of the cells with [35S]methionine. Analysis of the immunoprecipitates by NaDodSO4\/polyacrylamide gel electrophoresis showed a single peak of radioactivity corresponding to Mr 68,000. These results indicate that the liver is a site of alpha 2-PI production.<\/jats:p>","DOI":"10.1073\/pnas.79.18.5684","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T04:53:57Z","timestamp":1149051237000},"page":"5684-5687","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":19,"title":["Synthesis and secretion of alpha 2-plasmin inhibitor by established human liver cell lines."],"prefix":"10.1073","volume":"79","author":[{"given":"H","family":"Saito","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"L T","family":"Goodnough","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"B B","family":"Knowles","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D P","family":"Aden","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1982,9]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.79.18.5684","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T11:17:59Z","timestamp":1649848679000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.79.18.5684"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1982,9]]},"references-count":0,"journal-issue":{"issue":"18","published-print":{"date-parts":[[1982,9]]}},"alternative-id":["10.1073\/pnas.79.18.5684"],"URL":"https:\/\/doi.org\/10.1073\/pnas.79.18.5684","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1982,9]]},"assertion":[{"value":"1982-09-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}