The metabolism of l-rhamnose in Escherichia coli

Extracts of Escherichia coli, prepared from cells grown on l-rhamnose, contained a l-rhamnulose kinase (ATP:l-rhamnulose i-phosphotransferase, EC 2.7.1.5) which has been purified about 13-fold. The enzyme appears to be an SH enzyme, which catalyzes the phosphorylation of l-rhamnulose in the presence of ATP and some divalent metal ions but seems not to reactive with other sugars. Analytical studies on the phosphorulated sugar suggest that the reaction product is l-rhamnulose i-phosphate.

Evidence is present which indicates that the first step in the fermentation of l-rhamnose is the conversion of the methylpentose to l-rhamnulose followed by a phosphorylation of the ketose.