Abstract
Investigation was carried out on the difference of substrate specificity among isozymes with different blood acid-phosphatase, classified by agar-gel electrophoresis, and on the variance of substrate specificity in accordance with the growth of silkworm, Bombyx mori L. The results obtained are as follows:
1) None of the isozymes acts on β-GP, but all, except OO-type, have strong activity on α-NP and G-1-P. The activity of OO-type is lower than the other isozymes and particularly its activity value on α-NP is about one-fifth of CC and DD-type. The ratio of α-NP to NPP in OO-type is about 0.3, in AA-type it is 0.4-0.6 and in CC and DD-type it is about 0.8.
2) Not only in the case of α-NP as substrate but also in the case of NPP, the enzyme activity which begins decreasing at matured stage of larva, is not detected at middle pupal stage. Concerning the ratio of α-NP to NPP, CC and DD-type get to resemble OO-type at pupal stage.
3) That there is such difference in the ratio of α-NP to NPP is because that in the case with NPP as substrate there exists a band acting specificially on NPP (NPP-ase) besides the active band (α-NP-ase) detectable in the case with α-NP as substrate, and that the activities of both enzymes might be controlled by different genes respectively. It was also found that the ratio of α-NP to NPP changes in accordance with metamorphosis because the decrease of the activities of α-NP-ase and NPP-ase with metamorphosis does not coincide, but the former decreases in earlier stage.
