Studies on the multiple forms of aminopeptidase A in bovine seminal vesicle secretion

After gel filtration, anion exchange chromatography and chromatofocusing aminopeptidase A (AP-A) of bovine seminal vesicle secretion (VS-S) was found to exist in multiple forms. Depending on the pH used (pH 6.5-8.5) gel filtration of VS-S revealed 1-3 forms of AP-A. At pH 8.5 two dissimilar low-molecular-weight forms of AP-A converted into aggregated high-molecular-weight form. The aggregated AP-A was dissociated into an intermediate form with Triton X-100 and/or sodium deoxycholate and further into two low-molecular-weight forms with thiol compounds and neuraminidase. The aggregated, intermediate and low-molecular-weight forms of AP-A displayed some differences in catalytic properties, modifier characteristics and thermal inhibition.