Caratteristiche della fosfo-gluco-isomerasi di una pianta superiore |
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| Authors: | Renato Bianchetti |
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| Affiliation: | Laboratorio di Fisiologia Vegetale dell'Istituto di Scienze Botaniche dell'Universita di Milano Centro di studio sulle ossido-riduzioni nei vegetali del C.N.R. |
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| Abstract: | Abstract PHOSPHOGLUCOISOMERASE FROM PEA COTYLEDONS. — 6-P-glucose iso-merase has been purified from pea cotyledons. A 70-fold purification has been obtained by means of acetone fractionation and two absorption-elution steps on calcium phosphate gel. The partially purified enzyme is free of interfering activities. KM values of 2.5×10?4 and 10?4 been measured for glucose-6-P and fructose-6-P respectively. reaction, measured at pH 7.8 and 30° C., is 3.7 (Gl-6-PIFr-6-P). The enzyme is not inhibited by p-chloro-mercurybenzoate up to 10?3 M. Besides the substances already known to inhibit competitively the isomerase from animal tissues, the pea enzyme has been found to be competitively inhibited by ribose-5-P and by triosespho-sphates, the K1, being respectively 7×10?4 and 2.5×10?4. The properties of the pea enzyme are compared to those of animal tissues isomerase. The possible physiological significance of these properties is discussed. |
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