Add reverse enzymatic reactions

[cthoyt]

@sophiakrix and I are trying to reason over some PSI-MI files. We were looking for a term that represents the opposite of "deamination reaction" (MI:0985), but none is available. Would you be able to add an entry for "amination reaction"?

[pporrasebi]

We are generally reluctant to add new terms unless we have biological entities that can be annotated with them. So far, we have not found any cases of amination reactions that can be annotated with our CV. Could you please point to specific examples so we can see if there are use cases we can point to, please?