Trehalose Phosphate Phosphatase Research Articles

Anhydrobiosis in nematodes: Biosynthesis of trehalose

AbstractThe pathway for the synthesis of trehalose in Aphelenchus avenae was demonstrated. As in other systems, the enzymes involved in the synthesis of trehalose of A. avenae were found to be trehalose phosphate synthetase (TPS) and trehalosephosphate phosphatase (TPP). Some of the characteristics of trehalose phosphate synthetase were studied. It was found that the rate limiting step in the reaction is catalyzed by TPS. Partially purified TPS was specific for UDPG as the glucosyl donor, and showed a pH optimum of 8.0. The partially purified enzyme has a Km of 0.6 mM and a Vmax of 2.2 × 10−3 μmoles/mg protein min for glucose‐6‐phosphate, and a Km of 2.4 mM and Vmax of 2.5 × 10−3 μmoles/mg protein minfor UDPG.

Partial purification and properties of a highly specific trehalose phosphate phosphatase from Mycobacterium smegmatis.

A specific trehalose phosphate phosphatase was purified approximately 50-fold from Mycobacterium smegmatis. The enzyme had a pH optimum of about 7.0 and was stimulated by Mg(2+). The optimum concentration of Mg(2+) was about 1.5 x 10(-3)m. Of other divalent cations tested, only Co(2+) showed some activity. The K(m) for trehalose phosphate was found to be about 1.5 x 10(-3)m. The enzyme showed slight activity toward mannose-6-P and fructose-6-P but was inactive on a large number of other phosphorylated compounds. Citrate was a competitive inhibitor of the enzyme both with respect to trehalose phosphate concentration and Mg(2+) concentration. This inhibition appears to be due to chelation of Mg(2+) by this compound. Ethylenediaminetetraacetic acid and NaF were also inhibitors of the enzyme, but these inhibitions were noncompetitive.