UDP-4-amino-4-deoxy-L-arabinose formyltransferase (, UDP-L-Ara4N formyltransferase, ArnAFT) is an enzyme with systematic name 10-formyltetrahydrofolate:UDP-4-amino-4-deoxy-beta-L-arabinose N-formyltransferase. This enzyme catalyses the following chemical reaction
The activity is part of a bifunctional enzyme that also performs the EC 1.1.1.305 reaction.