K-108. AraL from B. subtilis Is a Sugar Phosphatase and Member of the Nitrophenyl Phosphatase Family of the HAD Superfamily

J. K. Hill, S. F. O'Handley;
Rochester Inst. of Technology, Rochester, NY.

The HAD (Haloacid Dehalogenase) superfamily is a diverse superfamily with a majority of the enzymes being phosphatases. One family of the HAD superfamily is the nitrophenyl phosphatase family, so named because the first family members were yeast enzymes found only to hydrolyze p nitrophenyl phosphate. Since that time, a number of enzymes with a variety of activities have been identified and characterized. There are pyridoxal phosphatases, a UMPase, phosphoglycolate phosphatases, and most recently, a sugar phosphatase from B. subtilis. We have cloned the araL gene, expressed and purified the AraL protein, and partially determined its activity. Like the other family members, AraL is a phosphatase, but unlike any other member, it is the first sugar phosphatase to be reported for this family. Currently, we have found activity on ribose 5-phosphate, but this may not be the best substrate, as araL is within the arabinose operon. If AraL degrades sugar phosphates found in the arabinose pathway, its cellular role may be to help regulate this important sugar metabolism pathway.