Biosynthesis of isovalthine

Liver homogenates could synthetize S-(isopropylcarboxymethyl) glutathione (GSIV) from isovaleric acid and glutathione, and GSIV thus formed was cleaved into L-allo-isovalthine by kidney glutathionase preparation. Isovaleric acid-l-C14 incorporated into GSIV without prior cleavage by the in vitro system. The discrepancy of configuration between urinary and in vitro synthesized isovalthine was discussed.