Nakano Vinegar Co., Ltd.

Yoshifumi Ohshima

Yoshiya Kawamura

Hajime Okumura

Mikio Yamada

Atsushi Ishikawa

Disclosed are a novel fructosylamine deglycase characterized by the specificity to amadori compounds of catalyzing oxidation of the compounds to produce an .alpha.-ketoaldehyde, an amine derivative and hydrogen peroxide; a method of producing the novel enzyme by cultivating microorganisms belonging to the genus Candida and having an ability of producing the novel enzyme; and a method of quantitative determination of amadori compounds by applying the novel enzyme to a sample containing amadori compounds to measure the amount of the hydrogen peroxide to be formed by the oxidation reaction or measure the amount of the oxygen to be consumed by the reaction to thereby obtain the amount of the amadori compounds from the measured value. The invention provides a novel enzyme characterized by the high specificity to the reaction with amadori compounds, especially that having therein a saccharide moiety as bonded to the .epsilon.-amino group, and also provides a method of producing the enzyme and a method of quantitative determination of amadori compounds with the enzyme. Using the enzyme, quantitative determination of amadori compounds, which is difficult by conventional enzymatic methods, is possible with ease. In particular, in measurement of the amount of a saccharified protein in a sample from a living body, which is an important index substance in diagnosis of diabetes, the enzymatic method of the invention of measuring fructosamine in the sample is hardly influenced by other interfering substances or impurities in the sample, the influence by them having been inevitable in conventional chemical methods. Accurate determination of the amount is possible by the method, and the method is free from the inconvenience of staining the kits and instruments used. For measuring glycohemoglobin, the method displays another characteristic feature that its operation is more simple and needs less labor and time than conventional methods.

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Handa, Japan

Yoshifumi Ohshima