
The enzyme is useful for the determination of creatinine in clinical analysis.
由来 | recombinant E. coli |
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系统名称 | Creatinine amidohydrolase |
EC编号 | 3.5.2.10 |
反应式 | Creatinine H2O Creatine |
The enzyme is useful for the determination of creatinine in clinical analysis.
由来 | recombinant E. coli |
---|---|
系统名称 | Creatinine amidohydrolase |
EC编号 | 3.5.2.10 |
反应式 | Creatinine H2O Creatine |
Appearance | white lyophilizate | |
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Activity | 600-750 U/mg | |
Contaminants | Catalase ≦0.5 U/U % | |
Stabilizer | sucrose | |
Storage condition | below -20℃ |
Molecular weight | ca. 170 kDa (gel filtration) |
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Structure | 6 subunits of 28 kDa (SDS-PAGE) |
Isoelectric point | 4.8 |
Michaelis constant | 3.4×10-2M (creatinine) |
4.3×10-2M ((creatine) | |
pH Optimum | 6.5–7.0 (Fig. 1) |
pH Stability | 7.0–11.0 (Fig. 2) |
Optimum temperature | 60–65℃ (Fig. 3) |
Thermal stability | below 60℃ (Fig. 4) |
Stability (liquid form) | stable at 37°C for at least two weeks (Fig. 5) |
Stability (powder form) | stable at 30°C for at least one month (Fig. 6) |
Inhibitors | Hg2+ |
Activators | Mg2+,Mn2+ |
The enzyme is useful for the determination of creatinine and creatine in clinical analysis.
The appearance of creatine is measured spectrophotometrically at 525 nm.
One unit (U) is defined as the amount of enzyme which produces 1 μmol of creatine per min at 37℃ and pH 6.8 under the conditions described below.
Sample: dissolve the lyophilized enzyme to a volume activity of 2–4 U/ml with ice-cold enzyme dilution buffer (Reagent G) immediately before measurement.
0.1 ml | Potassium phosphate buffer | (Reagent A) |
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0.8 ml | Creatinine solution | (Reagent B) |
0.1 ml | The terminated solution of step 4 | |
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0.9 ml | Distilled water | |
0.5 ml | α-Naphthol solution | (Reagent D) |
0.5 ml | Alkaline solution | (Reagent E) |
0.5 ml | Diacetyl solution | (Reagent F) |
Activity can be calculated by using the following formula:
Suzuki, M. and Yoshida, M. (1984)
A new enzymatic serum creatinine measurement based on an endogenous creatine-eliminating system
Clinica Chimica Acta, 143, 147–155.