Further studies on bovine serum amylase. 2. Affinity electrophoresis

The polymorphism of bovine serum amylase, which is controlled by the AmI locus, has previously only been demonstrated by starch gel electrophoresis. The addition of maltose to starch gels has been demonstrated to inhibit any subsequent separation of the AmI isozymes by starch gel electrophoresis. When electrophoresis was conducted in a support medium in the absence of starch no polymorphic variation was detected amongst samples from animals of different AmI phenotypes. The addition of starch to agarose gels has been shown to facilitate the subsequent detection of the AmI polymorphism by agarose/starch gel electrophoresis. The electrophoretic resolution of the AmI isozymes has been demonstrated to depend upon differences in affinity for starch rather than differences in net charge. The starch gel electrophoretic separation of the AmI isozymes is, therefore, another example of affinity electrophoresis. All the AmI amylases have been shown to share a common isoelectric point of pH 3.5.