Creatinase from Actinobacillus sp.

General description

Creatinase is a homodimer that catalyzes hydrolysis of creatine. It consists of two monomer subunits and two defined domains; N and C terminal domains. The C-terminal fold has both the α helices and anti-parallel β sheet within two structurally similar domains.In between these two domains, a sulfhydryl group acts as active site, and the activity is metal-independent.

Application

Creatinase mixed with sarcosine oxidase may be used to determine the level of creatine in different pH, temperature, enzyme ratio, and buffer concentration. It may also be used to determine the plasma creatinine level by using a centrifugal analyser.

Biochem/physiol Actions

Creatinase accelerates the conversion reaction of creatine and water molecule to sarcosine and urea. It always acts in homodimer state and is induced by choline chloride.

Physical properties

Isoelectric point: 4.6 ± 0.1
Michaelis constant: 1.9 x 10‾²M (Creatine)
Structure: 2 subunits per mole of enzyme
Inhibitors: Cu⁺⁺, Hg⁺⁺, Ag⁺
Optimum pH: 8.0
Optimum temp: 40°C
pH Stability: pH 5.5 − 9.0 (25°C, 16hr)
Thermal stability: Below 50°C (pH 7.5, 30 min)

Unit Definition

One unit will hydrolyze 1.0 μmole of creatine to urea and sarcosine per min at pH 7.5 at 37 °C.

Physical form

Lyophilized powder containing sugars and EDTA as stabilizers