the first is at the active-site hydrophobic pocket ( the catalytically productive site ) , where co2 is approximately 3.5 a from the zinc ion and interacts with his-94 , his-119 , val-121 , val-143 , leu-198 , thr-199 , the zinc ion , and the zinc-bound hydroxide ion .
C0043481
zinc
C0085057
zinc