Abstract
Plants comprise two active glucan phosphatases, Starch EXcess4 (SEX4) and Like Sex Four2 (LSF2). These phosphatases belong to the dual phosphatase (DSP) family of the protein tyrosine phosphatase (PTP) superfamily. DSP is a structurally diverse group and carbohydrate is the physiological substrate for glucan phosphatase family of enzymes. The X‐ray crystal structures of SEX4, LSF2 and human glucan phosphatase laforin revealed the primary mechanisms how glucan phosphatases bind carbohydrates and integrate them into the catalytic site. In vitro, enzymatic assays revealed that SEX4 preferentially removes phosphates attached to C6 position of glucose in starch while LSF2 and laforin remove phosphate groups attached to C3 position. However, little is known about the kinetics and regulatory mechanisms of carbohydrate dephosphorylation by SEX4 and LSF2. Here we define the enzymology of SEX4 and LSF2 using the generic substrate para‐nitrophenyl phosphate and physiologically relevant substrates, amylopectin, and glycogen.Support or Funding InformationSkidmore College Start‐up FundThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Published Version
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