Nonhistone protein purified from porcine kidney acts as a suicide substrate inhibitor on furin-like enzyme
Abstract
"AIM:
To search and purify a naturally occurring protein inhibitor of the furin-like enzyme from the porcine kidney.
METHODS:
Recombinant kexin, a furin-like enzyme, from the yeast secretion expression was used as a target enzyme. The inhibitor component was extracted and purified from the acetone powder of porcine kidney. The inhibitory activity was monitored using a fluorogenic peptide substrate Boc-Arg-Val-Arg-MCA at spectrofluorimeter.
RESULTS:
The purified inhibitor component is a basic protein with an isoelectric point over 9.5. Its partial N-terminal sequence of 22 residues was determined, showing a high homology with nonhistone chromosomal protein HMG-17 in which there are four sites composed of dibasic residues, susceptible to be cleaved by the furin-like enzyme. This nonhistone protein could strongly compete with the fluorogenic substrate. However, this nonhistone protein would be degraded as a substrate by kexin if it was incubated with the enzyme for long time before adding the fluorogenic substrate, and subsequently lost its temporary inhibitory activity.
CONCLUSION:
The nonhistone protein isolated from the porcine kidney functioned as a suicide substrate inhibitor for the furin-like enzyme."
Keywords:
To search and purify a naturally occurring protein inhibitor of the furin-like enzyme from the porcine kidney.
METHODS:
Recombinant kexin, a furin-like enzyme, from the yeast secretion expression was used as a target enzyme. The inhibitor component was extracted and purified from the acetone powder of porcine kidney. The inhibitory activity was monitored using a fluorogenic peptide substrate Boc-Arg-Val-Arg-MCA at spectrofluorimeter.
RESULTS:
The purified inhibitor component is a basic protein with an isoelectric point over 9.5. Its partial N-terminal sequence of 22 residues was determined, showing a high homology with nonhistone chromosomal protein HMG-17 in which there are four sites composed of dibasic residues, susceptible to be cleaved by the furin-like enzyme. This nonhistone protein could strongly compete with the fluorogenic substrate. However, this nonhistone protein would be degraded as a substrate by kexin if it was incubated with the enzyme for long time before adding the fluorogenic substrate, and subsequently lost its temporary inhibitory activity.
CONCLUSION:
The nonhistone protein isolated from the porcine kidney functioned as a suicide substrate inhibitor for the furin-like enzyme."