**Fast Immobilization of Human Carbonic Anhydrase II on Ni-Based Metal-Organic Framework Nanorods with High Catalytic Performance**

#### **Mengzhao Jiao 1, Jie He 1, Shanshan Sun 1, Frank Vriesekoop 2, Qipeng Yuan 1, Yanhui Liu 1,3,\* and Hao Liang 1,\***


Received: 2 March 2020; Accepted: 15 March 2020; Published: 6 April 2020

**Abstract:** Carbonic anhydrase (CA) has received considerable attention for its ability to capture carbon dioxide efficiently. This study reports a simple strategy for immobilizing recombinant carbonic anhydrase II from human (hCA II) on Ni-based MOFs (Ni-BTC) nanorods, which was readily achieved in a one-pot immobilization of His-tagged hCA II (His-hCA II). Consequently, His-hCA II from cell lysate could obtain an activity recovery of 99% under optimal conditions. After storing for 10 days, the immobilized His-hCA II maintained 40% activity while the free enzyme lost 91% activity. Furthermore, during the hydrolysis of p-nitrophenyl acetic acid, immobilized His-hCA II exhibited excellent reusability and still retained more than 65% of the original activity after eight cycles. In addition, we also found that Ni-BTC had no fixation effect on proteins without histidine-tag. These results show that the Ni-BTC MOFs have a grea<sup>t</sup> potential with high efficiency for and specific binding of immobilized enzymes.

**Keywords:** one-pot hydrothermal; immobilizing recombinant; His-hCA II; Ni-BTC nanorods
