Communications to the Editor 2813 amino acids.2 A maximum of 50% hydrolysis of the racemate was achieved in a few hours, which was not altered by addition of fresh enzyme and further incubation. The liberated L-amino acid was separated from the digest as usual, and recrystallized as glistening prisms from 50% alcohol; N caled. 11.8, found 11.7; [a] 25d +10.0°( 4.00% in H20); yield 80% on the chloroacetyl derivative. The chloroacetyl-D-allothreonine in the mother liquor was extracted, hydrolyzed with 2 N HC1, and isolated in 62% yield after neutralization and recrystallization from 50% alcohol; N found 11.7; [a] 26d -9.8°( 4.00% in H20).The optical rotation values of the allothreonine isomers are in agreement with those given by West and Carter6 and by Elliott,7 and the assignment of their configuration is in accord with that recently reported by Elliott7 on the basis of organic chemical procedures.We thank Dr. . E. Carter for a gift of dlallothreonine.
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