TASK DEFINITION: In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.
PROBLEM: Inhibition of testicular LDH-X from laboratory animals and man by gossypol and its isomers.

SOLUTION: LDH-X

PROBLEM: The catalytic competence of cytochrome P450 in the synthesis of serotonin from 5-methoxytryptamine in the brain: an in vitro study.

SOLUTION: cytochrome P450

PROBLEM: Losartan: a selective angiotensin II type 1 (AT1) receptor antagonist for the treatment of heart failure.

SOLUTION:
angiotensin II type 1 (AT1) receptor