A study on the inactivation of wheat carboxypeptidase. Implication of the transient active monomer and the half-site reactivity.
The mechanism of inactivation of carboxypeptidase from wheat at high pH was studied kinetically and spectrophotometrically. Inactivation of wheat carboxypeptidase is characterized by initial, transient high activity, soon followed by loss of activity, accompanied by an increase in both fluorescence intensity and anisotropy and a decrease in circular dichroism. A scheme was proposed in which the enzyme undergoes dissociation into monomers, the total activity of which becomes twice that of the normal dimer on a mass basis, and soon further denatures and aggregates. Treatment of the enzyme with a bifunctional reagent partly prevented denaturation of the monomer and hence increased the peptide synthetic activity.
Kunugi
S
S
Department of Applied Chemistry and Biotechnology, Fukui University, Japan.
Tanabe
K
K
Kondoh
T
T
Yokoyama
M
M
Ito
N
N
Nomura
A
A
Fukuda
M
M
D002268:Carboxypeptidases / Q000378:metabolism*; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008954:Models, Biological; D013053:Spectrophotometry; D014908:Triticum / Q000201:enzymology*
D002268:Carboxypeptidases