2-dimethoxyglutarate followed by enzymatic resolution afforded (4S)- and (4R)-4-methyl-2-oxoglutaric acid in an enantiomerically pure form. The activity of glutamic oxalacetic transaminase towards these compounds has been measured. Their enzymatic transamination provides an efficient synthesis of (4S)- and (4R)-4-methyl-L-glutamic acids which are very useful for characterisation of glutamate receptors