Which of the following enzymes does not contain Cu2+
Correct Answer: Xanthine oxidase
Description: Dopamine b-hydroxylase is a copper-containing enzyme involved in the synthesis of the catecholamines (norepinephrine and epinephrine), from tyrosine in the adrenal medulla and central nervous system.Ceruloplasmin, a copper-containing plasma protein synthesized by the liver, is a ferroxidase required for the oxidation of Fe2+ to Fe3+. Fe3+ is then bound to transferrin in blood.Cytochrome oxidase is a hemoprotein widely distributed in many tissues, having the typical heme prosthetic group present in myoglobin, hemoglobin, and other cytochromes. It contains two molecules of heme, each having one Fe atom that oscillates between Fe3+ and Fe2+ during oxidation and reduction. Fuhermore, two atoms of Cu are present, each associated with a heme unit.Hephaestin, a copper-containing ferroxidase homologous to ceruloplasmin, oxidizes Fe2+ to Fe3+ prior to expo. Iron is transpoed in plasma in the Fe3+ form by the transpo protein, transferrin.Ceain lysyl residues are modified by lysyl oxidase, a copper-containing protein that conves e-amino groups to aldehydes.Xanthine oxidase, which contains molybdenum and plays an impoant role in the conversion of purine bases to uric acid, and is of paicular significancein uricotelic animals.Ref: Harper&;s Biochemistry; 30th edition
Category:
Biochemistry
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