C. E. Lankford, L. Rode, V. T. Schuhardt
May 1, 1956
Citations
0
Influential Citations
2
Citations
Journal
Journal of Bacteriology
Abstract
Previous studies (Lankford et al., 1952) demonstrated that minute quantities of Dor i-methionine (0.001 to 0.01 ug S per ml) exert a stimulatory effect on the utilization of "DL" (inactive)-homocystine by selected strains of Brucella suis. The growth response to D-homocystine was found to be proportional to the quantity of methionine present, either as contamination of the commercial sample, or that added to the purified compound. Since our strains of B. suis failed to utilize purified DLhomocystine, although they utilized either cystine or methionine singly, this appeared to contradict the projected role (Davis, 1955) of homocyst(e)ine as a natural intermediate in the cysteine = methionine interconversions. The possibility was recognized, however, that the failure to respond to pure DL-homocystine may have been due to its stereoisomeric complexity. Therefore, the relation of methionine and other factors to the utilization of the isomers of homocystine has been investigated. Since previous studies of bacterial utilization of homocyst(e)ine have been limited to the "DL"-stereoisomeric complex, there is need for information whether bacteria, like the rat (Dyer and duVigneaud, 1935), are capable of utilizing both Dand Lhomocyst(e)ine for methionine synthesis (Rydon, 1948).