Abstract
Aerobacter aerogenes strain PRL-R3 possesses inducible enzyme pathways for the catabolism of d-xylose and d-arabitol. d-Xylose is the apparent inducer for d-xylose isomerase and d-xylulokinase. d-Arabitol is the apparent inducer for d-arabitol dehydrogenase and a separate d-xylulokinase. Both kinases had similar K(m) values and substrate specificities, and could not be separated by sucrose gradient centrifugation or polyacrylamide gel electrophoresis. They could be differentiated, however, by their separate regulation, their inhibition by antisera, and by the cold sensitivity of the kinase of the d-arabitol catabolic pathway.