One of the enzymatic methods is as follows: at first creatinine is converted to creatine by creatininase
Creatinine: This enzymatic method is based on the conversion of creatinine with the aid of creatininase
, creatinase, and sarcosine oxidase to glycine, formaldehyde, and hydrogen peroxide.
To measure urine creatinine, we used a coupled end-point enzymatic method in which urine creatinine is converted to creatine by creatininase
Urine creatinine concentrations were measured using Creatinine Plus Assay, which is a coupled enzymatic reaction using creatininase
, creatinase, and sarcosine oxidase (Roche Diagnostic, Indianapolis, Ind).
The Creatinine Plus assay (Roche Hitachi Modular, Roche Diagnostics) is an enzymatic creatininase
reaction approved for use in plasma or serum, with calibrators assigned by IDMS.
This method is based on the same reaction sequence as the Creatinine-PAP (phenol aminophenazone) method (29) consisting of 4 consecutive enzymatic steps via creatininase
, creatinase, sarcosine oxidase, and peroxidase, but using a different chromophore (2,4,6-triiodo-3-hydroxybenzoic acid) and a modified detergent composition.
The enzymatic method is based on the determination of sarcosine after conversion of creatinine with creatininase
, creatinase, and sarcosine oxidase.
One method was based on coupling of enzymatic bioassays using creatininase
, creatinase, and sarcosine oxidase and electrophoresic separation and amperometric detection of reaction products (46).
Total protein was determined by colorimetry using the biuret reaction and creatinine by an enzymatic method using creatininase
, both from Roche.