In enzymology, an aspartyltransferase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are L-asparagine and hydroxylamine, whereas its two products are NH<sub>3</sub> and L-aspartylhydroxamate.
This enzyme belongs to the family of transferases, specifically the aminoacyltransferases. The systematic name of this enzyme class is L-asparagine:hydroxylamine gamma-aspartyltransferase. Other names in common use include beta-aspartyl transferase, and aspartotransferase.