Abstract
On the determination of amino acid contents in serum, urine and foods, minimal medium for the microbioassay was established except cystine.
There are two questions in the case of cystine.
(1) The standard curve is low.
(2) The recovery is no good.
As it is thought that the fall of standard curve was due to the decomposition of cystine in the time of sterilization, the author observed the decomposition of cystine at the usual condition of sterilization (15 pounds, 10 minutes; autoclaving). And the decomposition of cystine was certified even in the exact condition of sterilization (15 pounds, 3 minutes, autoclaving).
