metalloenzyme

chemical compound

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June 30, 2026

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A metalloenzyme is a protein that contains a metal ion, which is essential for its catalytic activity. These metal ions act as cofactors, meaning they are nonprotein components required for an enzyme to function.123

Metalloenzymes play crucial roles in biological systems. For instance, they are involved in processes like digestion, as seen with carboxypeptidase, which contains a zinc ion. Catalase, another metalloenzyme, uses iron-porphyrin complexes to break down hydrogen peroxide. Hemoglobin, vital for oxygen transport, also features iron-porphyrin complexes. Other examples include chlorophyll, a magnesium-porphyrin complex, and vitamin B12, a cobalt complex.1

These metal ions are often bound directly to amino acid side chains within the protein structure. Transition metals like iron, cobalt, copper, and molybdenum are particularly important in biological chemistry.24

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coordination compound
Coordination compounds in nature
…processes, are metal complexes (metalloenzymes); for example, carboxypeptidase, a hydrolytic enzyme important in digestion, contains a zinc ion coordinated to several amino acid residues of the protein. Another enzyme, catalase, which is an efficient catalyst for the decomposition of
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…processes, are metal complexes (metalloenzymes); for example, carboxypeptidase, a hydrolytic enzyme important in digestion, contains a zinc ion coordinated to several amino acid residues of the protein. Another enzyme, catalase, which is an efficient catalyst for the decomposition of
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organosulfur compound
The sulfur atom
…copper (Cu) are crucial in metalloenzymes—for example, cytochrome C, in which the sulfur of methionine is coordinated to the iron in heme; the iron-sulfur proteins, in which cysteine sulfur is bound to iron; and molybdenum-containing enzymes, some of which involve dithiolate (two-sulfur) cofactors.
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…copper (Cu) are crucial in metalloenzymes—for example, cytochrome C, in which the sulfur of methionine is coordinated to the iron in heme; the iron-sulfur proteins, in which cysteine sulfur is bound to iron; and molybdenum-containing enzymes, some of which involve dithiolate (two-sulfur) cofactors.
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