Proteins are: Polypeptides + (cofactors, coenzymes, prosthetic groups, other modifications) z Polypeptides are covalently linked α-amino acids z Cofactors are non-amino acid components e.g. metal ions like Zn2+ in carboxypeptidase z Coenzymes are organic cofactors e.g. nucleotides in lactate dehydrogenase z Prosthetic groups are covalently attached cofactors e.g. heme in myoglobinProteins are: Polypeptides + (cofactors, coenzymes, prosthetic groups, other modifications) z Polypeptides are covalently linked α-amino acids z Cofactors are non-amino acid components e.g. metal ions like Zn2+ in carboxypeptidase z Coenzymes are organic cofactors e.g. nucleotides in lactate dehydrogenase z Prosthetic groups are covalently attached cofactors e.g. heme in myoglobin