In enzymology, a pyridoxamine-oxaloacetate transaminase (EC 2.6.1.31) is an enzyme that catalyzes the chemical reaction:

pyridoxamine + oxaloacetate ${\displaystyle \rightleftharpoons }$ pyridoxal + L-aspartate

Thus, the two substrates of this enzyme are pyridoxamine and oxaloacetate, whereas its two products are pyridoxal and L-aspartate.

This enzyme belongs to the family of transferases, specifically the transaminases, which transfer nitrogenous groups. The systematic name of this enzyme class is pyridoxamine:oxaloacetate aminotransferase. This enzyme participates in vitamin B₆ metabolism.