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Characterization of the enzymatic specificity of the IGF-dependent insulin-like growth factor binding protein-4

D Chelius1, C A Conover, M A Baldwin

  • 1Laboratory of Growth and Development, California Pacific Medical Center Research Institute, San Francisco, CA 94114, USA.

Growth Hormone & IGF Research : Official Journal of the Growth Hormone Research Society and the International IGF Research Society
|February 13, 2001
PubMed

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.

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