In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.

[EX Q]: Carnitine biosynthesis. Purification of gamma-butyrobetaine hydroxylase from rat liver.
[EX A]: gamma-butyrobetaine

[EX Q]: The (R)-omeprazole hydroxylation index reflects CYP2C19 activity in healthy Japanese volunteers.
[EX A]: (R)-omeprazole

[EX Q]: Toxic, halogenated cysteine S-conjugates and targeting of mitochondrial enzymes of energy metabolism.
[EX A]:
cysteine S-conjugates