Further studies on bovine serum amylase. 3. Affinity chromatography

The major bovine serum isoamylases controlled by the AmI locus have been examined by gel filtration. On Sephadex G-200 the isoamylases can be resolved into two classes. The AmI A and AmI B have apparent molecular weights of 307 000 daltons whilst the AmI C isozyme has an apparent molecular weight of 44 400 daltons. The separation of the isozymes into two classes according to their elution behaviour on Sephadex G-200 has been shown to be an affinity separation. All three AmI isozymes are eluted from a non-dextran media (BioGel A1.5m) with apparent molecular weights of 417 000 daltons. The affinity separation on Sephadex G-200 has been shown to be inhibited by the addition of 1% (w/v) maltose to the elution buffer. In the presence of 1 % (w/v) maltose all three AmI isozymes are coeluted from Sephadex G-200 with apparent molecular weights of 321000 daltons. The maltase and amylase activities of the AmI isozymes were eluted coincidentally under all the conditions studied.