A new class of phosphotransferases phosphorylated on an aspartate residue in an amino-terminal DXDX(T/V) motif.

摘要: When incubated with their substrates, human phosphomannomutase and L-3-phosphoserine phosphatase are known to form phosphoenzymes chemical characteristics of an acyl-phosphate. The phosphorylated residue in has now been identified by mass spectrometry after reduction the phosphoenzyme tritiated borohydride trypsin digestion. It is first aspartate a conserved DVDGT motif. Replacement either this motif asparagine or glutamate resulted complete inactivation enzyme. same mutations performed DXDST also enzyme, except for replacement second glutamate, which reduced activity only about 40%. This suggests that phosphatase. Data banks contained seven other phosphomutases phosphatases sharing similar, totally DXDX(T/V) at amino terminus. One these (beta-phosphoglucomutase) shown In conclusion, belong new phosphotransferase family amino-terminal serves as intermediate phosphoryl acceptor.