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Activity of platelet monoamine oxidase in apparently healthy subjects
Author(s) -
Koide Yayoi,
Sääf Jan,
Roos Svante B.,
Wahlund LarsOlof,
Wetterberg Lennart
Publication year - 1981
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/j.1399-0004.1981.tb00734.x
Subject(s) - monoamine oxidase , platelet , medicine , endocrinology , chemistry , biochemistry , enzyme
Monoamine oxidase activity was assayed in platelets from 32 apparently healthy subjects using phenethylamine as substrate and two concentrations of oxygen (0.06 and 0.12 mM). Apparent K m (μM) and V max (nmol/mg protein/5 min) values were estimated from double reciprocal plots. The means of the K m and V max values were both increased by a factor of about 1.6 when the oxygen concentration was elevated from 0.06 mM (K m = 2.96 and V max = 4.47) to 0.12 mM (L = 4.82 and V max = 7.18). The frequency distribution of the V max values was not clearly unimodal, especially at the higher oxygen concentration. The Vmax values of the women were significantly higher than those of the men but no sex difference was obtained for the K m values. The overall velocity (v) at 10 μM phenethylamine was highly correlated to the V max values both at low and high oxygen concentrations (r=0.99 and 0.98, respectively).