β- N-Acetylhexosaminidase and α- d-mannosidase from the epigonal lymphomyeloid organ of the nurse shark ( Ginglymostoma cirratum)

Abstract

1. 1. Lymphomyeloid (lymphohaemopoietic) tissues are rich in glycosidases probably contained within leucocytes. The glycosidases β- N-acetylhexosaminidase and α- d-mannosidase found in the epigonal organ—a prominent lymphomyeloid tissue of the nurse shark Ginglymostoma cirratum—were purified and preliminary characterized. 2. 2. The enzyme β- N-acetylhexosaminidase was assayed as N- acetyl-β- d-glucosaminidase but was shown to have also N- acetyl-β- d-galactosaminidase activity. The pH optima were 4.5 and 4.2 for these two substrates. The enzyme was purified 40-fold by gel filtration. By isoelectric focusing the enzyme showed multiple forms with pI's = 6.0, 6.5, 6.7 and 6.9. The molecular weight was 144,000 ± 13,000 (SD) estimated by gel filtration. 3. 3. α- d-mannosidase was purified 30-fold by gel filtration. Isoelectric focusing in a narrow pH range gave the pI values 7.3, 7.6 and 7.85. The main pH optima were at 3.3, 3.7 and 4.5. The molecular weight was 275,000 ± 19,000 (SD).