A Sensitive Radiochemical Assay Method for s=Aminolevulinic Acid Synthetase*
نویسندگان
چکیده
1. A new sensitive method for measuring &aminolevulinic acid (ALA) synthetase activity has been developed based on the incorporation of 14C-succinate into ALA. The method is extremely sensitive and will permit assay of the enzyme in normal tissues and in small amounts of tissue for which the existing calorimetric methods are inadequate. Difficulties due to aminoacetone synthesis are eliminated. 2. The procedure has been applied to liver homogenates and mitochondrial suspensions, to reticulocytes, and to bacterial extracts. 3. It has been found that the normal level of ALA synthetase activity in guinea pig liver mitochondria is even less than hitherto believed from calorimetric assays and cannot with confidence be said to be significantly above zero. 4. An inhibitor of ALA synthetase activity has been shown to be present in the insoluble fraction of normal liver mitochondria.
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