Purification and properties of neutral alpha-1,4 glucosidase from human seminal plasma

Following a preliminary fractionation of neutral alpha-glucosidase (E.C. 3.2.1.20) from human seminal plasma, we have shown by ion exchange chromatography, Sephadex G-200 filtration, and adsorption chromatography that this alpha-glucosidase activity corresponded to two isoenzymes having the same ability to hydrolyse p-nitrophenyl-alpha-D-glucopyranoside. Both isoenzymes present a heat-stable fraction at 60 degrees C, require the presence of divalent cations in the incubation medium to demonstrate their glycolytic activity, and are inhibited by maltotriose and maltose. They have a molecular weight of approximately 200,000 daltons and different sedimentation profiles on sucrose density gradient. This basic knowledge appears to be the prerequisite for further studies dealing with the importance of such isoenzymes as markers of epididymal function in male fertility.