Purification of riboflavin-binding proteins from bovine plasma and discovery of a pregnancy-specific riboflavin-binding protein.
Riboflavin-binding proteins have been purified from bovine plasma using flavinyl agarose beads. At least three major protein bands, migrating in regions assigned to the beta- and gamma-globulins of plasma, are observed by cellulose acetate electrophoresis. These proteins coelute from a calibrated Sephadex G-100 column in the volume corresponding to a molecular weight of approximately 150,000; a small amount of another riboflavin-binding protein (molecular weight approximately 37,000) is also present. Polyacrylamide gel electrophoresis of the proteins,  with detection by autoradiography of those having tightly bound [2-14C]riboflavin, reveals one protein band which is present only in preparations from pregnant cows. This protein has been purified to apparent homogeneity by storing the mixture of riboflavin-binding proteins at 8 degrees C for 3 weeks, which precipitates the other, less stable proteins. Hence, bovine plasma, like that of the laying hen, contains a number of riboflavin-binding proteins, one of which correlates with pregnancy.
D000818:Animals; D002352:Carrier Proteins / Q000097:blood* / Q000302:isolation & purification; D002417:Cattle; D005260:Female; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood* / Q000302:isolation & purification; D012256:Riboflavin / Q000097:blood*
D002352:Carrier Proteins; D011257:Pregnancy Proteins; D012256:Riboflavin