Interconversion of active and inactive forms of phosphorylase and glycogen synthetase in oocytes and embryos of the loach (Misgurnus fossilis L.).

Glycogen synthetase (EC 2.4.1.11) from oocytes and embryos of the loach (Misgurnus fossilis L.) has been found only in the D-form. The intensive glycogen accumulation during oogenesis did not correspond with the glycogen synthetase interconversion in the I-form.In isolated oocytes and embryos of the loach insulin transforms glycogen synthetase into the form which is desensitized for ATP inhibition. Insulin treatment enhancesV max without affecting theK m (UDP-glucose) only with an excess of activator-glucose-6-P. Simultaneously insulin treatment converts the phosphorylase (EC 2.4.1.1.) into the latent form.