Hydrolases;
Acting on carbon-nitrogen bonds, other than peptide bonds;
In other compounds
BRITE hierarchy

1-aminocyclopropane-1-carboxylate aminohydrolase (isomerizing)

1-aminocyclopropane-1-carboxylate + H2O = 2-oxobutanoate + NH3 (overall reaction) [RN:R00997];
(1a) 1-aminocyclopropane-1-carboxylate = 2-aminobut-2-enoate;
(1b) 2-aminobut-2-enoate = 2-iminobutanoate (spontaneous);
(1c) 2-iminobutanoate + H2O = 2-oxobutanoate + NH3 (spontaneous)

R00997
Reaction

1-aminocyclopropane-1-carboxylate [CPD:C01234];
H2O [CPD:C00001];
2-aminobut-2-enoate [CPD:C17234];
2-iminobutanoate [CPD:C20905]

A pyridoxal 5'-phosphate enzyme. The enzyme, found in certain soil bacteria and fungi, catalyses the ring opening of 1-aminocyclopropane-1-carboxylate, the immediate precursor to ethylene, an important plant hormone that regulates fruit ripening and other processes. The enzyme releases an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination. The latter reaction, which can occur spontaneously, can also be catalysed by EC 3.5.99.10, 2-iminobutanoate/2-iminopropanoate deaminase. The enzyme has been used to make fruit ripening dependent on externally added ethylene, as it removes the substrate for endogenous ethylene formation.

EC 3.5.99.7 created 1981 as EC 4.1.99.4, transferred 2002 to EC 3.5.99.7, modified 2014