Abstract
SummaryThe vit. B12 assay using a mutant strain of E. coli was modified by addition of methionine-free casein hydrolysate to a mineral medium. This method gave better growth and allowed a more accurate estimation of the vit. B12 than previous methods using the same organism. The assay required only 40-48 hr as compared with 7-9 days when E. gracilis is used; the set-up, too, is very simple. The test proved satisfactory for the determination of vit. B12 in human serum. The vit. B12 content of sera of healthy subjects determined by this method ranged from 200 to 1000 μμg/ml, while sera of patients suffering from pernicious anemia contained only 50-130 μμg/ml.
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Schedule a callMore From: Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)
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