TY - JOUR
T1 - Kinetic mechanism and substrate specificity of nitroalkane oxidase
AU - Heasley, Carl J.
AU - Fitzpatrick, Paul F.
N1 - Funding Information:
This research was supported in part by Grant MCB 95-06060 from the National Science Foundation. P.F.F. is an Established Investigator of the American Heart Association.
PY - 1996/8/5
Y1 - 1996/8/5
N2 - Nitroalkane oxidase from Fusarium oxysporum catalyzes the oxidation of nitroalkanes to aldehydes, transferring the electrons to oxygen to form hydrogen peroxide. The steady-state kinetic patterns have been determined with nitroethane, 1-nitropropane, and 1-nitropentane as substrates. In all three cases, the data fit best to a ping pong kinetic mechanism. The pH dependences of the V/K values for 1-nitropentane and phenylnitromethane show that an amino acid residue on the enzyme with a pK(a), value of 6.7 must be unprotonated for activity with both substrates. A second group must be protonated for activity. The pK(a), value of this group matches the pK(a), values of the nitroalkanes, 9.3 with nitropropane and 6.7 with phenylnitromethane, establishing that the nitroalkane must be in the neutral rather than the anionic form for catalysis.
AB - Nitroalkane oxidase from Fusarium oxysporum catalyzes the oxidation of nitroalkanes to aldehydes, transferring the electrons to oxygen to form hydrogen peroxide. The steady-state kinetic patterns have been determined with nitroethane, 1-nitropropane, and 1-nitropentane as substrates. In all three cases, the data fit best to a ping pong kinetic mechanism. The pH dependences of the V/K values for 1-nitropentane and phenylnitromethane show that an amino acid residue on the enzyme with a pK(a), value of 6.7 must be unprotonated for activity with both substrates. A second group must be protonated for activity. The pK(a), value of this group matches the pK(a), values of the nitroalkanes, 9.3 with nitropropane and 6.7 with phenylnitromethane, establishing that the nitroalkane must be in the neutral rather than the anionic form for catalysis.
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U2 - 10.1006/bbrc.1996.1122
DO - 10.1006/bbrc.1996.1122
M3 - Article
C2 - 8769086
AN - SCOPUS:0030570782
VL - 225
SP - 6
EP - 10
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 1
ER -