Instrumentation Laboratory

Instrumentation Laboratory S.r.l.

501 Instrumentation Laboratory S.p.a.

Maurizio D'Alterio

Dario Frontini

Mauro Papagni

An aqueous liquid composition is disclosed. The composition comprises a stabilized glucose oxidase solution having a pH of from about 6.0 to 8.0 and contains phosphate at a concentration of 1500 to 2500 mM/l. The glucose oxidase retains at least 80% of its activity after 10 days at 37.degree. C. The glucose oxidase is preferrably derived from Aspergillus niger, has a concentration of from about 5 to about 50 IU/ml and a pH range of from about 7.1 to about 7.3.

Stabilized glucose oxidase from Aspergillus Niger

This invention relates to a process for stabilizing the enzyme urate oxidase (commonly known as uricase) in liquid form, and to the relative compositions which can then be obtained, with particular reference to compositions containing a Trinder reagent. According to the process of the invention, uricase can be stabilized in liquid form by adding to the composition containing the enzyme a substituted or unsubstituted dicarboxylic acid containing from 2 to 5 carbon atoms, and preferably 4 or 5. Aspartic acid has shown to be particularly effective in providing said stabilizing activity in liquid uricase compositions containing a Trinder reagent.

Stabilization of the enzyme urate oxidase in liquid form

Spontaneous aspecific coloration in so-called Trinder reagents which can alter subsequent colorimetric determinations is inhibited by adding compounds of the chelating agent class to the solution. The resultant compositions contain a peroxidase enzyme, a phenylpyrazone derivative, a compound of phenolic or aromatic amine structure and a stabilizer. Preferred stablizers are ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA).

Stabilized trinder reagent

Spontaneous aspecific coloration in so-called Trinder reagents which can alter subsequent colorimetric determinations is inhibited by adding compounds of the chelating agent class to the solution. The resultant compositions contain a peroxidase enzyme, a phenylpyrazone derivative, a compound of phenolic or aromatic amine structure and a stabilizer. Preferred stabilizers are ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA).

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Brugherio, Italy

Maurizio D'Alterio