A New Role of Phosphoglucose Isomerase. Involvement of the Glycolytic Enzyme in Aldehyde Metabolism

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Z. S. Agadjanyan^*, L. F. Dmitriev, and S. F. Dugin

Cardiology Research Center, Ministry of Public Health of Russian Federation, ul. Cherepkovskaya 15A, 121552 Moscow, Russia; fax: (7-095) 414-6699; E-mail: zira-aga@yandex.ru

^* To whom correspondence should be addressed.

Received December 28, 2004; Revision received March 22, 2005

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Lipid peroxidation in biological membranes is accompanied by malonic dialdehyde (MDA) formation, but the problem of its further metabolism in cytoplasm remains unsolved. The experimental data obtained in this work showed that the liver fraction prepared by centrifugation at 10,000g contained phosphoglucose isomerase and enzymes of the glyoxalase system. In this fraction in the presence of GSH there is an aggregate of reactions taking place both in membranes (lipid peroxidation) and outside membranes (MDA conversion to methylglyoxal and further to neutral D-lactate). This means that MDA is slowly accumulated because it is a substrate of aldehyde isomerase (MDA <--> methylglyoxal). Most probably, phosphoglucose isomerase serves as this enzyme. We concluded that D-lactate should be regarded as the end product of two different parametabolic reactions: lipid peroxidation or protein glycation.

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KEY WORDS: lipid peroxidation, malonic dialdehyde, methylglyoxal, aldehyde isomerase, D-lactate

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