N-Acetyl-beta-glucosaminidases in human spleen.
1. The N-acetyl-beta-glucosaminidase of human spleen has been separated by gel electrophoresis into two components, an acidic form A and a basic form B. 2. The two forms are readily separated on DEAE-cellulose and have been concentrated 50-fold and sevenfold respectively. 3. They show similar K(m) values towards 4-methylumbelliferyl N-acetyl-beta-d-glucosaminide, and have the same pH optima when compared in citrate, phosphate or acetate buffers. They are inhibited to a similar extent by acetate, heparin, N-acetylgalactosaminolactone, N-acetyl-beta-d-galactosamine and N-acetyl-beta-d-glucosamine. Specificity for C-4 orientation is not absolute and p-nitrophenyl beta-galactosaminide is also hydrolysed but at a rate only 11.6% of that for the corresponding glucosaminide. 4. N-Acetyl-beta-glucosaminidase B is stable over a wider pH range than is N-acetyl-beta-glucosaminidase A, and is less easily denatured by heat. 5. Tissue fractionation indicates that both the A and B forms are present in the lysosomal fraction, whereas the supernatant contains the A form only. 6. Evidence is presented to indicate that the A form contains a number of sialic acid residues.
D000135:Acid Phosphatase / Q000032:analysis; D002467:Cell Nucleus / Q000201:enzymology; D002482:Cellulose; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004355:Drug Stability; D004586:Electrophoresis; D005696:Galactosidases / Q000378:metabolism; D005782:Gels; D005966:Glucuronidase / Q000032:analysis; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008247:Lysosomes / Q000201:enzymology*; D008928:Mitochondria / Q000201:enzymology*; D009438:Neuraminic Acids / Q000032:analysis; D011489:Protein Denaturation; D013154:Spleen / Q000166:cytology / Q000201:enzymology*
D005782:Gels; D009438:Neuraminic Acids; D002482:Cellulose; D000135:Acid Phosphatase; D005696:Galactosidases; D006026:Glycoside Hydrolases; D005966:Glucuronidase