|
KMID : 0376219690060020161
|
|
Chonnam Medical Journal
1969 Volume.6 No. 2 p.161 ~ p.171
|
|
|
Studies on NAD Nucleosidase in Erythrocytes
|
|
|
|
|
Abstract
|
|
|
Studies were made to find out the orientation of NAD nucleosidase in the erythrocyte membrane, and the relationship between NAD nucleosidase activity and the uptake of nicotinic acid or nicotinamide by various mammalian erythrocytes.
1. The unhemolyzed intact erythrocytes of rabbit, hydrolyzed NAD at the same rate as the hemolysate or the membrance fraction did. Moreover, the uptake of nicotinamide-7-^(14)C by the erythrocytes was inhibited by results strongly suggest that the enzyme is oriented to the outer surface of the erythrocyte membrane.
2. The enzyme activity was found to be high in the erythrocytes of rabbit, sheep, swine and calf, but very low in those of human, rat and mouse. The erythrocytes with lower NAD nucleosidase activity took up nicotinic acid at a much greater rate than those with higher enxyme activity.
Although the uptake of nicotinamide by erythrocytes was found to be roughly correlated in an inverse manner with the NAD nucleosidase activity of erythrocytes, the correlation did not hold as definitely as in the case for the uptake of nicotinic acid.
3. The rate of uptake of nicotinic acid or nicotinamide by various mammalian erythrocytes showed some agreement with the preference which any erythrocytes show to ward nicotinic acid or nicotinamide utilizable as precursor of NAD biosynthesis.
From these results it was suggested that NAD nueleosidase oriented outwardly in the erythrocyte membrane might play a regulatory role in the uptake process of nicotinic acid by erythrocytes.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|
|