A substrate in a sample can be determined quantitatively by measuring colorimetrically superoxide ion generated by treating the sample with a specific oxidase corresponding to the substrate to be determined, said oxidase treatment and measuring of the generated superoxide ion being conducted by using a reagent composition comprising (a) an oxidase, (b) peroxidase, (c) a phenol and/or an amine, (d) a thiol compound, (e) a color producing reagent to be reduced, and if necessary (f) a chelating agent. Further, the peroxidase can be replaced by (b') iron complex of porphyrin or ion chelate of complexane.
使用与待测底物相对应的特定氧化酶处理样品后,可通过比色法测量生成的超氧离子,从而定量测定样品中的底物,所述氧化酶处理和测量生成的超氧离子是通过使用试剂组合物进行的,该试剂组合物包括 (a) 氧化酶、(b)
过氧化物酶、(c)
苯酚和/或胺、(d)
硫醇化合物、(e) 待还原的发色试剂,以及必要时 (f)
螯合剂。此外,
过氧化物酶还可以用(b')
卟啉铁络合物或络合物的离子螯合物代替。