Analysis of Free Amino Acids in Mammalian Brain Extracts

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A. L. Ksenofontov^1*, A. I. Boyko², G. V. Mkrtchyan², V. N. Tashlitsky³, A. V. Timofeeva¹, A. V. Graf^4,5, V. I. Bunik^1,3, and L. A. Baratova^1*

¹Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; E-mail: ksenofon@belozersky.msu.ru, baratova@belozersky.msu.ru

²Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, 119991 Moscow, Russia

³Lomonosov Moscow State University, Faculty of Chemistry, 119991 Moscow, Russia

⁴Lomonosov Moscow State University, Faculty of Biology, 119991 Moscow, Russia

⁵Faculty of Nano-, Bio-, Informational and Cognitive Technologies at Moscow Institute of Physics and Technology, 123098 Moscow, Russia

^* To whom correspondence should be addressed.

Received June 28, 2017; Revision received July 19, 2017

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An optimized method for analysis of free amino acids using a modified lithium-citrate buffer system with a Hitachi L-8800 amino acid analyzer is described. It demonstrates clear advantages over the sodium-citrate buffer system commonly used for the analysis of protein hydrolysates. A sample pretreatment technique for amino acid analysis of brain extracts is also discussed. The focus has been placed on the possibility of quantitative determination of the reduced form of glutathione (GSH) with simultaneous analysis of all other amino acids in brain extracts. The method was validated and calibration coefficient (K_GSH) was determined. Examples of chromatographic separation of free amino acids in extracts derived from different parts of the brain are presented.

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KEY WORDS: brain extracts, free amino acids, GSH, amino acid analysis, lithium-citrate buffer system, reduced glutathione

DOI: 10.1134/S000629791710011X

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