as this splitting of the 1359 cm-1 band with d-proline in d2o can not be interpreted only by the replacement of the c = n+1-h proton by deuterium , the carboxylate of the imino acid probably interacts with the enzyme through some proton ( s ) exchangeable by deuterium ( s ) in d2o .
C0033382
proline
C0020931
imino acid