Characterization of the enzymatic specificity of the IGF-dependent insulin-like growth factor binding protein-4 (IGFBP-4) protease.
The insulin-like growth factor (IGF)-dependent IGF binding protein-4 protease secreted by cultured adult human fibroblasts was recently identified as pregnancy-associated plasma protein-A (PAPP-A). In this study we showed that in addition to human IGFBP-4 the IGF-dependent IGFBP-4 protease also digests recombinant rat IGFBP-4 into two fragments by specifically cleaving at the carboxyl-terminal side of methionine at position 131 for rat IGFBP-4. Thus the cleavage site is at the KMKV site, which is not represented in other IGFBPs. While kallikrein may cleave at this site, its action is not specific.
Chelius
D
D
Laboratory of Growth and Development, California Pacific Medical Center Research Institute, San Francisco, CA 94114, USA.
Conover
C A
CA
Baldwin
M A
MA
Spencer
E M
EM
D000818:Animals; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D017077:Culture Media, Conditioned / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000378:metabolism; D007610:Kallikreins / Q000378:metabolism; D008666:Metalloendopeptidases / Q000737:chemistry* / Q000378:metabolism; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization; D013379:Substrate Specificity
D017077:Culture Media, Conditioned; D018974:Insulin-Like Growth Factor Binding Protein 4; D007610:Kallikreins; D008666:Metalloendopeptidases; D011266:Pregnancy-Associated Plasma Protein-A