Isolation, purification and characterization of low molecular weight 110mAg-binding proteins from the rat and goat...

Low molecular weight 110mAg-binding proteins have been purified from the goat and rat testis using a combination of acetone fractionation, gel filtration and ion-exchange chromatography. Both the rat and goat 110mAg-binding proteins existed in three isoforms, although the goat isoforms carried higher net negative charge than the corresponding isoforms of the rat. The average molecular weight of the goat isoforms was 8000 daltons, whereas that of the rat isoforms was 6300. The goat 110mAg-binding protein (a mixture of all the isoforms) was stable when heated at 85 degrees C for 15 min. The isoform II of the rat 110mAg-binding protein showed little absorbance at 280 nm, although the corresponding isoform of the goat protein did show significant absorbance at the same wavelength.