title: Automated measurement of amylase isoenzymes with 4-nitrophenyl-maltoheptaoside as substrate and use of a selective amylase inhibitor.
abstract: We automated a kinetic procedure for determining amylase isoenzymes in serum and urine samples. We used 4-nitro-phenylmaltoheptaoside as substrate and a selective amylase inhibitor with the Abbott-VP bichromatic system. By use of the maximum differences between pancreatic (P) and salivary (S) amylase activities remaining after inhibition by the selective inhibitor and by use of the linear range, a one-point standard method for calibration is proposed for determining amylase activities between about 50 and 1500 U/L when the P/S ratio exceeds 0.2. Results correlated well with those by electrophoresis and the Phadebas method (r = 0.99 for both pancreatic and salivary amylase). Reproducibilities (CVs) were 1.5% to 5.5% for pancreatic amylase and 1.4% to 3.3% for salivary amylase in serum, 0.8% to 2.0% for pancreatic amylase and 0.8% to 2.3% for salivary amylase in urine.
mesh_terms: D000367:Age Factors; D000681:Amylases / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000378:metabolism; D001322:Autoanalysis; D004588:Electrophoresis, Cellulose Acetate; D005960:Glucosides / Q000378:metabolism; D006027:Glycosides / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000032:analysis / Q000037:antagonists & inhibitors; D008875:Middle Aged; D012016:Reference Values; D014908:Triticum
chemical_list: D005960:Glucosides; D006027:Glycosides; D007527:Isoenzymes; C036167:4-nitrophenyl maltoheptaoside; D000681:Amylases