Article: article from journal or magazin.
Determination of intracellular prolyl/glycyl proteases in intact living human cells and protoporphyrin IX production as a reporter system
Chemistry and Biology
PT - Journal Article PT - Research Support, Non-U.S. Gov't
The determination of enzyme activity or inhibition in intact living cells is a problem in the development of inhibitors for intracellular proteases. The production of fluorescent protoporphyrin IX (PpIX) from the nonfluorescent (N)-Gly/Pro-5-aminolevulinic acid (ALA) substrates was used to evaluate the prolyl/glycyl-specific dipeptidylpeptidase IV (DPPIV)-like and prolyloligopeptidase (POP)-like activities of human cells. The results demonstrated that whereas POP-like activity could be attributed to the actual POP, the DPPIV-like activity could be related to actual DPPIV only in one colon cell line. In the other breast and colon cell lines, DPPIV-like activity was intracellular and displayed by other prolyl-specific aminopeptidases. Our experiments also demonstrated the involvement of glycyl-specific proteases in the processing of ALA precursors. These observations have important consequences for the development and evaluation of selective inhibitors for these enzymes
Adenosine Deaminase/metabolism/Aminolevulinic Acid/analogs & derivatives/Antigens,CD26/Breast Neoplasms/enzymology/Pathology/Cell Line,Tumor/Colonic Neoplasms/Cysteine Endopeptidases/analysis/Drug Design/Female/Fluorescent Dyes/Glycoproteins/Humans/Kinetics/Male/methods/Protease Inhibitors/chemical synthesis/pharmacology/Protoporphyrins/biosynthesis/Serine Endopeptidases/Substrate Specificity
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