Metal-organic frameworks (MOFs) have exciting potential for biomimetic studies of enzymes, yet construction of high-fidelity models at the metal nodes is challenging. Nonetheless, biomimetic MOFs have significant advantages, such as increased stability and ease of separation, over their enzymatic and homogeneous counterparts, making them particularly attractive for industrial applications. Here, we demonstrate biomimetic behavior of Zn hydroxide moieties inside a MOF with structural and reactivity characteristics of carbonic anhydrase. Similar to the biological system, the MOF binds CO2 by an insertion mechanism into the Zn-OH bond, leading to significant adsorption of CO2 (3.41 mmol/g). In reactivity mimicking that of the enzyme, the material also catalyzes the oxygen isotope exchange between water and carbon dioxide. Overall, these results provide the strongest evidence yet of metal nodes in MOFs bearing high structural fidelity to enzymatic active sites.