Is there an enzyme for digestion of IgA2-only?

There is no known enzyme that targets IgA2-only since the amino acids in the hinge regions of IgA2 is present also in IgA1. However, IgASAP Sub1 will digest IgA1-only.

What enzyme should be selected for the digestion of IgA1?

IgASAP Sub1 specifically targets IgA1 and exhibits a faster reaction time (1 hour) compared to IgASAP Sub1+2 (16-18 hours). The cleavage site of IgASAP Sub1+2 is located six amino acids above that of IgASAP Sub1, resulting in the absence of potentially O-glycosylated residues on the Fab fragments. This characteristic can be advantageous in certain cases.