4OEM:
reference: The amino-acid substituents of dipeptide substrates of cathepsin C can determine the rate-limiting steps of catalysis., Rubach JK, Cui G, Schneck JL, Taylor AN, Zhao B, Smallwood A, Nevins N, Wisnoski D, Thrall SH, Meek TD, Biochemistry. 2012 Sep 25;51(38):7551-68. doi: 10.1021/bi300719b. Epub 2012 Sep, 13. PMID: 22928782

This OCA Structure page
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