The Thr197 is hydrogen bonded to the OH- on the zinc ion. jmolButton("zap; load pdb CA1v9e1.pdb; zoom 120;select all;spacefill off;set spiny 15;spin on", "View 8", 8, "CA") If you are on a personal connection, like at home, you can run an anti-virus scan on your device to make sure it is not infected with malware. National Institute of Allergy and Infectious Diseases, National Institute of General Medical Sciences, Carbonic anhydrase is an example of a "perfect" enzyme, which performs its reaction as fast as carbon dioxide molecules can diffuse to it. H 2 CO 3 + H 2 O ⇌ H 3 O + + HCO 3−. jmolButton("zap;load;zoom 120;select all;wireframe 20;spacefill 80;select atomno=21;spacefill 120;label Zn;color label white;select atomno=22;label O;color label white;select atomno=16;label B;color label white;select atomno=20;label N;color label white;set spiny 15;spin on", "View 10", 10, "model_2") There are at least seven human isozymes that appear predominantly in red blood cells, secretory tissues, and muscle. Performance & security by Cloudflare, Please complete the security check to access. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. The aqua ligands in [Zn(OH2)6]2+ have a pKa of 9.6, so three histidines delocalize less positive charge from the Zn(II) than 5 aqua (water) ligands. Every hydrogen on each aqua ligand stabilizes some positive charge. Carbonic anhydrase, enzyme found in red blood cells, gastric mucosa, pancreatic cells, and renal tubules that catalyzes the interconversion of carbon dioxide (CO2) and carbonic acid (H2CO3). Carbonic acid can be considered to be a diprotic acid from which two series of salts can be formed—namely, hydrogen carbonates, containing HCO 3−, and carbonates, containing CO 32−. Updates? Plasma, Blood, and Related Proteins and Reagents, Custom & Predesigned DNA Oligos & qPCR Probes, Advanced Genomics – CRISPR Technology & RNAi, Carbonic Anhydrase from bovine erythrocytes lyophilized powder, ≥2,000 W-A units/mg protein, Carbonic Anhydrase from bovine erythrocytes ≥95% (SDS-PAGE), specific activity ≥3,500 W-A units/mg protein, lyophilized powder, Carbonic Anhydrase from bovine erythrocytes BioReagent, suitable for GFC marker, Carbonic Anhydrase from bovine erythrocytes For use as a marker in SDS-PAGE, Carbonic Anhydrase from bovine erythrocytes non-denaturing PAGE marker, Carbonic Anhydrase II bovine ≥90% (SDS-PAGE), recombinant, expressed in, Carbonic Anhydrase Isozyme II from bovine erythrocytes lyophilized powder, ≥3,000 W-A units/mg protein, Carbonic Anhydrase Isozyme II from bovine erythrocytes Isoelectric focusing marker, pI 5.4, Carbonic Anhydrase Isozyme II from bovine erythrocytes lyophilized powder, ≥2,000 W-A units/mg protein, Carbonic Anhydrase II human recombinant, expressed in, Carbonic Anhydrase I from human erythrocytes, Carbonic Anhydrase I from human erythrocytes Isoelectric focusing marker, pI 6.6, Carbonic Anhydrase Isozyme II human ≥80%, powder, ≥3,000 W-A units/mg protein. Thus it is apparent that these enzyme classes have evolved independently to create a similar enzyme active site. The zinc also coordinates a hydroxide ion (red). Journal of Biological Chemistry 275, 5521-5526. CO 2 + H 2 O ⇌ H 2 CO 3 The predominant species are simply loosely hydrated CO 2 molecules. H. 2. 3-+ H + OH-+ CO. 2. • The alpha carbonic anhydrase enzymes have been well studied, leading to an understanding of how they work. In our lungs, oxygen diffuses into the blood, binds to hemoglobin and is transported to all the cells of our body (see the. jmolButton("rotate y -15;select 93, 95, 118;wireframe 20;spacefill 80;colour [58,144,255];color label yellow;select atomno=740;label His93;select atomno=944;label His118;select atomno=763;label His95;select atomno=2056;color label yellow;label Zn;spacefill 120;select atomno=2056,atomno=764,atomno=743,atomno=945;;wireframe 20", "View 3", 3, "histidine") PDB-101 builds introductory materials to help beginners get started in the subject ("101", as in an entry level course) as well as resources for extended learning. CO. 3 . jmolButton("zoom 120;select all;spacefill off;wireframe 20;spacefill 80;select atomno=4532;spacefill 100;select atomno=2056;spacefill 150;SELECT 93, 95, 118, 63, 198, 244, 91, 116, 105, 66, 61, 6, 197;spacefill off;wireframe 20;select atomno=4178;spacefill 100;SELECT 93, 95, 118, 91, 116, atomno=4532;labels off;monitor 1549 4532;monitor 56 4538;monitor 56 4533;monitor 500 4260;monitor 525 4266;monitor 497 485;monitor 1547 4533;monitor 4538 4159;monitor 4159 4260;monitor 4260 4178;monitor 4260 4266;monitor 4266 4579;monitor 4178 4532;monitor 4178 1556;set spiny 15;spin on", "View 6", 6, "hydrogen")