Distribution of the two forms of guinea-pig beta 2-microglobulin originally detected in urine

Two distinct forms of beta 2-microglobulin (beta 2m) have been detected in pooled guinea-pig serum from outbred animals using ultrafiltration, gel filtration and ion exchange chromatography. These two forms probably correspond to the two beta 2m forms, with different electrophoretic mobility, that have been previously identified in guinea-pig urine. In solubilized membranes from perfused guinea-pig livers only the basic form of beta 2m could be found. These results may indicate that the two beta 2m forms should not be ascribed to genetic polymorphism but rather are a result of post-translational modification.