3CMS:
reference: Engineering enzyme subsite specificity: preparation, kinetic characterization, and X-ray analysis at 2.0-A resolution of Val111Phe site-mutated calf chymosin., Strop P, Sedlacek J, Stys J, Kaderabkova Z, Blaha I, Pavlickova L, Pohl J, Fabry M, Kostka V, Newman M, et al., Biochemistry 1990 Oct 23;29(42):9863-71. PMID: 2271625

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