Purification of bovine urinary beta(2)-microglobulin and its biochemical characteristics

In this study, bovine beta(2)-m was purified from urine by ion-exchange chr omatography and gel chromatography, and the characteristics were compared w ith those of colostral beta(2)-m by the immunological reactivity, isoelectr ic points, peptide map, and amino acid sequence. The characteristics of pur ified urinary beta(2)-m were consistent with those of the colostral beta(2) -m. The urinary and colostral beta(2)-m possessed the same polypeptide chai n consisting of 98 amino acids, and its molecular weight is 11.8 kDa. Furth ermore, four isoforms of beta(2)-m were found. The isoelectric points were different from each other.