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]: Isolation and function of the amino acid transporter PAT1 (slc36a1) from rabbit and discrimination between transport via PAT1 and system IMINO in renal brush-border membrane vesicles.
[EX A]: amino acid

[EX Q]: Probing the Role of the Vancomycin E-Ring Aryl Chloride: Selective Divergent Synthesis and Evaluation of Alternatively Substituted E-Ring Analogues.
[EX A]: Vancomycin

[EX Q]: Efficient induction of apoptosis in HeLa cells by a novel cationic porphycene photosensitizer.
[EX A]:
porphycene