Organic acidurias : proceedings of the ninth symposium of the Society for the Study of Inborn Errors of Metabolism / edited by J. Stern and C. Toothill.

  • Society for the Study of Inborn Errors of Metabolism.
Date:
1972
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Organic acidurias : proceedings of the ninth symposium of the Society for the Study of Inborn Errors of Metabolism / edited by J. Stern and C. Toothill. Source: Wellcome Collection.

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    METHYLMALONIC ACIDURIA 13 Table II. Methylmalonyl CoA muíase activity in leucocytes Units S.H. D.D. Mother of S.H. Father of S.H. Normal Adults Mean 1 unit = 1 m/irnole methylmalonic acid utilised/min./10®cells Fig. 2. The mixture containing 0-3 ml of a leucocyte suspension, 1-5 ml of a preparation with approximately 250 m^imoles methyl¬ malonyl CoA prepared from propionyl CoA and Naj '^COg, and 1 -2 ml 0-25 M tris/HCl pH 7-5 was incubated for 30 min. at 37°. Effect of Vitamin on Methylmalonyl CoA Mutase Activity Although methylmalonyl CoA mutase activity in the leucocyte homogenate from the affected child was not increased in the presence of added cyancobalamin, this might have been due to the fact that 5'- deoxyadenosylcobalamin, the specific co-enzyme in the reaction, had not been formed from the inactive cyancobalamin. The assay was therefore repeated, with the separate addition of both 5'-deoxyadenosylcobalamin and methylcobalamin, the incubation being carried out in subdued light to avoid any breakdown of the specific co-enzyme. The results are shown in Table III. No mutase activity was observed when no co-factor was added or when methylcobalamin was present but a significant activity, 9-5 mjumoles/lO® cells/min., was induced in the presence of 5'-deoxya- denosylcobalamin in a concentration of 10^ M. This is approximately 0 0 15-4 5-2 63 0, 18-8, 92'8, 36-6, 54 0 53 04