Ma. Khandkar et al., ALLOXAN-DIABETES ALTERS KINETIC-PROPERTIES OF THE MEMBRANE-BOUND FORM, BUT NOT OF THE SOLUBLE FORM, OF ACETYLCHOLINESTERASE IN RAT-BRAIN, Biochemical journal, 307, 1995, pp. 647-649
We examined the effects of alloxan-diabetes on the kinetic properties
of the soluble and the membrane-bound forms of acetylcholinesterase (A
ChE) in rat brain. The K-m (0.15 mM) and V-max. (1.5 mmol/min per mg o
f protein) of the soluble form of the enzyme were unchanged in the dia
betic animals. The membrane-bound enzyme in the control group displaye
d a lower K-m (0.09 mM) and a higher V-max. (7.2 mmol/min per mg of pr
otein) compared with the soluble form of the enzyme; the diabetic stat
e caused a significant increase (40%) in both K-m and V-max.. K-i(s) v
alues were about 3-4 times higher for the membrane-bound enzyme in bot
h control and diabetic animals. The results suggest that membrane bind
ing and membrane alterations in diabetes can significantly influence t
he kinetic properties of AChE.