S. M. Birnbaum, J. Greenstein
1953
Citations
0
Influential Citations
10
Citations
Journal
Archives of biochemistry and biophysics
Abstract
Abstract Chloroacetyl- dl -homoserine lactone was synthesized. After opening the ring at pH 8, and treating with hog kidney acylase I, dl -homoserine ([α]D = −8.8 ° in water and +18.3 ° in 2 N HCl) was obtained in 72% yield. From the mother liquor, chloroacetyl- d -homoserine was separated, yielding on HCl hydrolysis the lactone of d -homoserine · HCl ([α]D = +26.7 ° in water). Refluxing of the lactone at pH 8 resulted in d -homoserine in 60% yield ([α]D = +8.6 ° in water and −18.2 ° in 2 N HCl). A sample of the lactone of l -homoserine · HCl prepared by refluxing l -homoserine with HCl yielded [α]D = −27.0 ° in water. N-Acetyl-S-benzyl- dl -homocysteine was subjected at pH 7.5 to the action of acylase I, yielding S-benzyl- l -homocysteine in 85% yield ([α]D = +27.2 ° in 2 N HCl) and N-acetyl-S-benzyl- d -homocysteine. The latter compound after refluxing with HCl followed by neutralization yielded S-benzyl- d -homocysteine in 65% yield with [α]D = −27.3 °. From the S-benzyl derivatives, l - and d -homocystine were prepared by du Vigneaud's procedure, with [α]D respectively of +77.5 ° and −77.5 °. The l -enantiomorphs of homoserine and S-benzylhomocysteine are readily oxidized by Crotolus adamanteus venom l -amino acid oxidase, and the corresponding d -enantiomorphs by hog kidney d -amino acid oxidase. By means of these preparations it was determined that the l -and d -enantiomorphs of the two amino acids were more than 99.9% optically pure.