Use of L-leucyl-3-carboxy-4-hydroxyanilide as substrate for determining the activity of microsomal aminopeptidase in serum.
We describe a colorimetric method for assay of microsomal aminopeptidase (EC 3.4.11.2) activity in serum. We use a new substrate, L-leucyl-3-carboxy-4-hydroxyanilide, p-xylenol as coupler, and sodium metaperiodate as oxidizing reagent. The colored substance formed by the oxidative condensation between p-xylenol and 5-aminosalicylic acid absorbs maximally at 635 nm, and can be directly measured in serum. In a previous method for this enzyme, L-leucyl-beta-naphthylamide was used as substrate and beta-naphthylamine, a carcinogenic reagent used as a standard in making the assay, was unsuitable for routine use. We found a close correlation between results obtained with the new, safer method and with the previous method.
Shimamoto
M
M
Takewaki
S
S
Sakuraoka
S
S
Nagasawa
T
T
Kuroiwa
K
K
Kodama
O
O
Akatsuka
T
T
D000626:Aminopeptidases / Q000097:blood*; D000636:Aminosalicylic Acids / Q000378:metabolism; D000813:Anilides; D001660:Biliary Tract Diseases / Q000175:diagnosis; D018826:CD13 Antigens; D002863:Chromogenic Compounds / Q000032:analysis; D004796:Clinical Enzyme Tests / Q000379:methods*; D003124:Colorimetry; D005260:Female; D006801:Humans; D007930:Leucine / Q000031:analogs & derivatives*; D008107:Liver Diseases / Q000175:diagnosis; D019804:Mesalamine; D011247:Pregnancy; D012995:Solubility; D013997:Time Factors; D014992:Xylenes / Q000378:metabolism
D000636:Aminosalicylic Acids; D000813:Anilides; D002863:Chromogenic Compounds; D014992:Xylenes; D019804:Mesalamine; C046671:leucyl-3-carboxy-4-hydroxyanilide; D000626:Aminopeptidases; D018826:CD13 Antigens; D007930:Leucine; C016834:3,5-xylenol