Assay of dipeptidyl peptidase IV in serum by fluorometry of 4-methoxy-2-naphthylamine.
A new fluorometric assay for determining dipeptidyl peptidase IV (DPP IV; EC 3.4.14.5) was developed. The synthetic substrate glycyl-L-proline-4-methoxy-2-naphthylamide (20 mmol/L), Tris buffer (50 mmol/L, pH 8.3), and serum (20 microL) are mixed and incubated. The reaction is stopped with citrate (100 mmol/L, pH 4.0) and the released 4-methoxy-2-naphthylamine is measured fluorometrically. The mean value of DPP IV activity in serum for 64 healthy subjects was 58 (SD 16) mumol of 4-methoxy-2-naphthylamine released per liter of serum per minute. The proposed procedure is sensitive, rapid, and accurate and can easily be automated.
D015081:2-Naphthylamine / Q000031:analogs & derivatives / Q000032:analysis*; D000328:Adult; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000097:blood*; D005470:Fluorometry / Q000379:methods; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008875:Middle Aged; D009281:Naphthalenes / Q000032:analysis*; D012016:Reference Values
D009281:Naphthalenes; C013112:4-methoxy-2-naphthylamine; D015081:2-Naphthylamine; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4