table 8-1 Some Inorganic Elements That Serve as Cofactors for Enzymes C Cytochrome oxidase Fe Cytochrome oxidase, catalase, peroxidase Pyruvate kinase Hexokinase, glucose 6-phosphatase, pyruvate kinase M Arginase, ribonucleotide reductase Mo Dinitrogenase Urease Se Glutathione peroxidase Zn Carbonic anhydrase, alcohol dehydrogenase, carboxypeptidases A and B