Kikkoman Corporation

Daiichi Pure Chemicals Co., Ltd.

Seishin Pharmaceutical Co., Ltd.

Kohichiro Tobe

Kazunori Saito

Shoichi Tokutake

Kazuo Kotani

Tadashi Tomikura

The present invention provides a maltooligoside derivative represented by the formula: ##STR1## wherein n denotes an integer 3-5, R represents an aromatic chromophoric group, X represents a group &gt;CHCH.sub.2 N.sub.3 or &gt;C.dbd.CH.sub.2, and Y represents a hydrogen atom, a substituted or unsubstituted hydrocarbon group or an alkyl- or arylsulfonyl group, a reagent for determining .alpha.-amylase activity which comprises said maltooligoside derivative as an effective ingredient, and a process for determining .alpha.-amylase activity, characterized in that said maltooligoside derivative and coupled enzymes are added to an .alpha.-amylase containing sample to conduct an enzymatic reaction and a liberated aromatic chromophoric compound is quantitatively determined. The compound of the present invention is very useful as a substrate for determining .alpha.-amylase activity, and .alpha.-amylase activity can be easily measured accurately in a short time by using the reagent without affection of the other ingredients contained in the sample.

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Noda, Japan

Kohichiro Tobe