| Autor: |
Clark Bublitz, Albert L. Lehninger |
| Rok vydání: |
1961 |
| Předmět: |
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| Zdroj: |
Biochimica et Biophysica Acta. 47:288-297 |
| ISSN: |
0006-3002 |
| DOI: |
10.1016/0006-3002(61)90289-x |
| Popis: |
Aldonolactonase of the soluble fraction of rat liver has been purified 110-fold in a yield of 34% by isoelectric precipitation and heat treatment in the presence of Mn++, fractionation with acetone, and finally chromatography on carboxymethylcellulose columns. During the purification of the enzyme, the aldonolactonase activity and the activity in stimulating conversion of L -gulonate to L -ascorbate by the L -gulonolactone oxidase of rat liver microsomes accompanied each other in an essentially constant ratio. The aldonolactonase thus was identified as catalyzing the lactonization of L -gulonate (reaction a) prior to the oxidation of the lactone (reaction b): L -gulonate ⇆ L -gulonolactone + H 2 O (a) L -gulonolactone + 1 2 O 2 → L -ascorbate + H 2 O (b) Aldonolactonase was shown to catalyze the net accumulation of equilibrium quantities of lactone from free L -gulonate. The tissue distribution and substrate specificity of the enzyme are discussed in relation to the ability of various species to synthesize L -ascorbic acid. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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