Inactivation et réactivation complètes de la phosphomonoestérase alcaline et interchangeabilité des métaux actifs

摘要: 1. 1. Purified alkaline phosphatase (phosphomonoesterase from dog's intestine) has been completely inactivated by prolonged dialysis against bidistilled water and reactivated. The hydrolytic power obtained, superior to that of the initial product, attains maximal 700 millimolecules β-glycerophosphate sodium per minute gramme nitrogen, at a ph 8,8, 37° C (Qp = 170.000). 2. 2. reactivation observed after incubation for 2 hours enzyme with alanine (1.10−2M), 8,8 addition magnesium ions. Under same conditions, other divalent cathions (Ca++, Fe++, Mn++ Zn++) reactivate various degrees. optimum concentration these is: very weak Zn++ Fe++ (1.10−7M), stronger (1.10−3M) Ca++ while, Mg++, there is threshold activity its greatest efficacy above 1.10−2M. 3. 3. Preliminary aminoacid indispensable; if this neglected, 4. only Mg++ and, lesser degree, can be active agents, though much smaller extent than incubation, C, in presence alanine. Probably partly due reversion denaturation aminoacid, rather slowness latter's reaction enzyme. Incubation metallic ions, whether before or alanine, not really effective. whole process, therefore, takes place as metal combined immediately enzyme. 5. 4. purified fluorides, orthophosphates pyrophosphates, prevents aminoacids cathions. Conversely, preliminary strongly interferes inhibiting action orthophospates pyrophosphates. We may deduce anions last-named salts combine structural element group phosphatases. 6. 5. It emphatically pointed out particularly those forming complexes, on can, rule, effective only products, certain definite metal-concentrations which vary each them. In opposite case function substances natural complexes preparations. frequent contradictions question found literature must attributed fact; different, easily reproduceable results may, indeed, obtained according method followed. 7. 6. importance facts discussed regarding constitution phosphatase. interchangeability metals does argue favour hypothesis exist, organs, phosphatases, specifically contains some peculiar tissue it found. Magnesium or, zinc, appears most common mineral constituent catalytically