{"title":"Purification and characterization of four components of rat caseins","authors":"Masaaki Hirose , Toshio Kato , Kenji Omori , Makoto Takeuchi , Masaaki Yoshikawa , Ryuzo Sasaki , Hideo Chiba","doi":"10.1016/0005-2795(81)90127-6","DOIUrl":null,"url":null,"abstract":"<div><p>Rat casein components (C1-, C3A-, C3B- and C4-casein) were extensively purified from rat milk, and the properties of these proteins were compared with those of other caseins including rat C2-casein. C1-casein was precipitated by a low concentration of CaCl<sub>2</sub> (1.5 mM). Both C3A- and C3B-casein were less sensitive to Ca<sup>2+</sup> than were C1- and C2-casein, and the presence of 20 mM CaCl<sub>2</sub> was required at 37°C for their precipitation. C4-casein was absolutely insensitive to Ca<sup>2+</sup>. This protein exhibited the ability to stabilize all of the other rat casein components against Ca<sup>2+</sup>-dependent precipitation. In addition, C4-casein contained sialic acid, galactose and <span><math><mtext>N-</mtext><mtext>acetylgalactosamine</mtext></math></span>. Therefore, C4-casein appears to be a bovine ϰ-casein-like protein.</p></div>","PeriodicalId":100165,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Protein Structure","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1981-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0005-2795(81)90127-6","citationCount":"5","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biochimica et Biophysica Acta (BBA) - Protein Structure","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0005279581901276","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 5
Abstract
Rat casein components (C1-, C3A-, C3B- and C4-casein) were extensively purified from rat milk, and the properties of these proteins were compared with those of other caseins including rat C2-casein. C1-casein was precipitated by a low concentration of CaCl2 (1.5 mM). Both C3A- and C3B-casein were less sensitive to Ca2+ than were C1- and C2-casein, and the presence of 20 mM CaCl2 was required at 37°C for their precipitation. C4-casein was absolutely insensitive to Ca2+. This protein exhibited the ability to stabilize all of the other rat casein components against Ca2+-dependent precipitation. In addition, C4-casein contained sialic acid, galactose and . Therefore, C4-casein appears to be a bovine ϰ-casein-like protein.