Investigations of in vivo methionine racemization in mammalian tissues

The racemization rate of methionine at pH 7.4 and 100 degrees C was determined to be similar to that of aspartic acid. However, analyses of dentin and ocular lens nucleus samples from known age Rhesus monkeys showed that unlike aspartic acid, methionine does not undergo in vivo racemization in mammalian proteins.