Effect of anticoagulants in colorimetric assay for basic carboxypeptidases.
Carboxypeptidases (CP) in plasma and sera serve as regulators of anaphylatoxins such as C3a and C5a. The activity of CP can be measured by determining hippuric acid after cleavage of the small synthetic substrate hippuryl-L-arginine. Although a colorimetric assay is convenient for determining hippuric acid generated by CP, we noticed that some anticoagulants, such as citrate, interfere with the color development of the reagents used. EDTA and heparin provide an appropriate value. EGTA used as anticoagulant also provides an appropriate value. Therefore, concentration of citrate in samples should be controlled to be constant for background subtraction.
Komura
Hidefumi
H
Department of Anesthesiology and Resuscitology Intensive and Critical Care, Nagoya City University School of Medicine, Aichi, Japan.
Obata
Kyoko
K
Campbell
William
W
Yumoto
Miho
M
Shimomura
Yasuyo
Y
Katsuya
Hirotada
H
Okada
Noriko
N
Okada
Hidechika
H
D000925:Anticoagulants; D001120:Arginine / Q000031:analogs & derivatives*; D002268:Carboxypeptidases / Q000097:blood*; D019343:Citric Acid; D003124:Colorimetry / Q000379:methods*; D003951:Diagnostic Errors; D004492:Edetic Acid; D004533:Egtazic Acid; D004789:Enzyme Activation; D006493:Heparin; D006626:Hippurates / Q000032:analysis*; D006801:Humans
D000925:Anticoagulants; D006626:Hippurates; D019343:Citric Acid; D004533:Egtazic Acid; C001650:hippuryl-L-arginine; D006493:Heparin; D001120:Arginine; D004492:Edetic Acid; D002268:Carboxypeptidases; C030514:hippuric acid