Alpha-mannosidase in human red cells.
1. A search for lysosomal hydrolases and related enzymes has been made in hemolysates from human and rabbit red cells. Apart from acid phosphatases, significant activities were found only for alpha-mannosidase, neutral alpha-glucosidase and beta-hexosaminidase. 2. alpha-Mannosidase (alpha-D-mannoside mannohydrolase, EC 3.2.1.24) activity per cell in human red blood cells was 200-times lower than in white cells. The optimal pH was 5.5--6.0. Electrophoresis on cellulose acetate showed three bands. Hemolysates from four patients with mannosidosis were not deficient in alpha-mannosidase. pH activity curves and elctrophoretic pattern were similar to those of controls. From its biochemical and genetic properties, it is concluded that red cell mannosidase differs from the lysosomal acid mannosidase.
D000818:Animals; D002239:Carbohydrate Metabolism, Inborn Errors / Q000201:enzymology; D004586:Electrophoresis; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000201:enzymology; D008358:Mannose / Q000378:metabolism; D008361:Mannosidases / Q000378:metabolism*; D011817:Rabbits; D014018:Tissue Distribution
D008361:Mannosidases; D008358:Mannose