Ajinomoto Co., Ltd.

Toshimi Mizukoshi

Wataru Hoshino

Uno Tagami

Yuya Kodama

Hiroaki Nishiuchi

Kazuyuki Kubota

Junko Yamazaki

Olga Aleksandrovna Sofyanovich

Dmitriy Aleksandrovich Cheshev

V Elena Matrosova

Vsevolod Aleksandovich Serebryanyy

The present invention provides a means and method useful for measurement of a total branched-chain amino acid concentration. Specifically, the present invention provides a modified enzyme in which at least one amino acid residue is mutated so as to improve a property of a leucine dehydrogenase which is associated with the measurement of the total branched-chain amino acids, such as, for example, substrate specificities of leucine dehydrogenase for total branched-chain amino acids, activity of leucine dehydrogenase for any branched-chain amino acids, and thermal stability of leucine dehydrogenase; and a method of analyzing the total branched-chain amino acids, comprising measuring the total branched-chain amino acids contained in a test sample using the modified enzyme.

Modified leucine dehydrogenase

The present invention provides a method of measuring an endogenous low-molecular-weight compound specifically and conveniently with high sensitivity. Using the particular sulfur-containing amino acid derivative, a method of measuring an endogenous low-molecular-weight compound specifically and conveniently with high sensitivity can be provided.

Sulfur-containing amino acid derivative

A yeast extract containing a peptide, such as &#x3b3;-Glu-X and &#x3b3;-Glu-X-Gly, wherein X can represent an amino acid or an amino acid derivative other than Cys and derivatives thereof, is prepared by culturing a yeast in a medium containing a peptide such as &#x3b3;-Glu-X, &#x3b3;-Glu-X-Gly and X-Gly, and preparing a yeast extract from the obtained cells.

Yeast extract containing &#x3b3;-Glu-X or &#x3b3;-Glu-X-Gly and a method for producing the same

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Kanagawa, Japan

Toshimi Mizukoshi