{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T13:32:53Z","timestamp":1791639173013,"version":"4.3.4"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"1","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1986,11,15]]},"abstract":"<jats:p>Bovine kappa-casein was fractionated at pH 8.0 on DEAE-Sepharose with an NaCl gradient, followed by DEAE-cellulose chromatography using a decreasing pH gradient from pH 6.0 to 4.5. At least ten components could be identified, each differing in N-acetylneuraminic acid (NeuAc) and\/or phosphorus content. Two components appeared to be multiply-phosphorylated, but did not contain NeuAc. The possible significance of this finding in relation to the mode of phosphorylation and glycosylation in vivo is discussed. A carbohydrate-free fraction as well as two NeuAc-containing fractions were compared in their substrate behaviour towards the action of the milk-clotting enzyme chymosin at pH 6.6 and 30 degrees C. To this end the trichloroacetic acid-soluble reaction products were analysed by high-performance gel-permeation chromatography. In order of increasing carbohydrate content the kcat. values found ranged from 40 to 25 s-1 and the Km values from 9 to 3 microM; the overall substrate properties of these components as reflected by the kinetic parameter kcat.\/Km ranged from 5 to 8 microM-1 X S-1. Irreversible polymerization of the carbohydrate-free fraction brought about a more-than-2-fold increase in Km, the kcat. value remaining virtually constant. The kcat.\/Km found for the cleavage of whole kappa-casein at pH 6.6 was of the same magnitude as the kcat.\/Km found for the polymerized carbohydrate-free fraction (i.e. about 3 microM-1 X S-1). No indication of substrate inhibition was found for the carbohydrate-free fraction.<\/jats:p>","DOI":"10.1042\/bj2400087","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T20:57:04Z","timestamp":1439240224000},"page":"87-97","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":131,"title":["Characterization of bovine <i>\u03ba<\/i>-casein fractions and the kinetics of chymosin-induced macropeptide release from carbohydrate-free and carbohydrate-containing fractions determined by high-performance gel-permeation chromatography"],"prefix":"10.1042","volume":"240","author":[{"given":"H J","family":"Vreeman","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S","family":"Visser","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C J","family":"Slangen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J A","family":"Van Riel","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/240\/1\/87\/588957\/bj2400087.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/240\/1\/87\/588957\/bj2400087.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,25]],"date-time":"2021-11-25T16:43:50Z","timestamp":1637858630000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/240\/1\/87\/22532\/Characterization-of-bovine-casein-fractions-and"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1986,11,15]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1986,11,15]]}},"URL":"https:\/\/doi.org\/10.1042\/bj2400087","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[1986,11,15]]}}}