Abstract
1.
1. The kinetic properties of alkaline phosphatase from the leg muscle of
Poekilocerus bufonius were investigated.
2.
2. The specific activity of the leg muscle enzyme was found to be higher than those of the fore-gut, mid-gut and hind-gut enzymes of
P. bufonius.
3.
3. The activity of the leg muscle enzyme was inhibited by phenylalanine as the
V
max was decreased, whereas the apparent
K
m value was not affected by the addition of phenylalanine.
4.
4. The enzyme has a pH optimum of 9.6, and the activity reached a maximum at 75°C and the enzyme was stable at 65°C.
5.
5. The activity of leg muscle alkaline phosphatase was activated by Mg
2+, whereas the enzyme activity was not significantly affected by Na
+ and Ca
2+.
6.
6. Mn
2+, Zn
2+ and Fe
3+ were all shown to be specific inhibitors of leg muscle alkaline phosphatase.