Purification, characterization, and expression of rat epididymal β-D-Galactosidase

Abstract

The purpose of the present study is to purify, kinetically characterize and measure the amount of soluble acid β-D-galactosidase (EC 3.2.1.23) in different anatomical regions (caput, corpus, and cauda) of the adult rat epididymis. Based upon SDS-PAGE analysis, the subunit molecular mass of the caput and cauda enzyme is ~85,000 daltons while the corpus enzyme is ~50,000 daltons. The apparent K(m) and V(max) values are 67, 24, and 59 μM and 5.0, 1.88, and 6.3 μM/min./-mg protein for the enzyme purified from the caput, corpus, and cauda regions of the epididymis, respectively. However, no regional differences in the amount of soluble enzyme protein are observed. These data demonstrates regional differences in the activity of epididymal acid β-D-galactosidase and suggest that the observed regional differences in enzyme activity may be due to posttranslational modifications.