Human blood cells sialidases
Marchesini, S.; Cestaro, B.; Lombardo, A.; Sciorelli, G.; Preti, A.
Biochemistry International 8(1): 151-158
1984
ISSN/ISBN: 0158-5231 PMID: 6477594 Document Number: 238128
The conditions of a linear assay for 4-methylumbelliferyl-alpha-D-N-acetyl-neuraminic acid (4-MU-NeuAc) sialidase activity in human lymphocytes, granulocytes, platelets and red cells plasma membranes have been determined. Lymphocytes and granulocytes have the same pH curve with two maximums at pH 4.0 and 4.8; however lymphocytes show a higher specific activity and a higher Km value. Sialidase activity detected in red cells plasma membranes has again a double-peak pH curve with maximums at pH 4.2 and pH 4.6, and specific activity levels less than one/30 compared to the other blood cells preparations. Platelets have a sialidase activity of the same magnitude as granulocytes, with an optimum pH at 4.2.