Check https://bmcbiotechnol.biomedcentral.com/articles/10.1186/s12896-018-0420-7

Also check https://link.springer.com/article/10.1007/s00894-016-3119-5

Are there crystal structures of these proteins available? If so, you will be able to see which residues are surrounding the active site. Also, the literature on these enzymes, if there is any, may contain information about their substrate preferences.

I would first do a BLAST of the sequences, and compare the alignment. The catalytic dyad/triad are quite conserved, so if you have any crystal structure in PDB (and probably there is), you can identify your catalytic residues. Once you do that, you can compare among your enzymes, and observe the differences. Since they present lots of families and super-families (and some unassigned), you'll see some differences among this group. Maybe even if you submit the sequences to PFAM you can see some differences between them.

Chinaza Godswill Awuchi Thank you so much for your references.

Adam B Shapiro Unfortunately, there is no crystal structure of these proteins available now. I will check further articles. Thank you for your recommendations.

Lorenzo Briganti Sourav Roy