Copper involves collagen synthesis by:
Correct Answer: Lysyl oxidase
Description: Ans: a (lysyl oxidase) Ref: Vasudevan 4th ed/ p. 239, 240.Collagen Svnthesis:-Collagen is synthesised by fibroblasts intracellularly as procollagen and then secreted. The extra- cellular procollagen is then cleaved to form tropocollagen.Inside fibroblasts, polypeptides are synthesised, proline and lysine residues are hydroxylated by prolyl hydroxylase and lysyl hydroxylase and glycosylation of lysine takes place. Then the procollagen molecules are secreted.Outside the cell, procollagen is cleaved by fibroblast specific peptidases forming tropocollagen which are then assembled into collagen. Finally, covalent crosslinks are formed. Collagen fibres are strengthened by covalent cross links between lysine and hydroxyl lysine residues.The cross links are formed by lysyl oxidase which is a copper containing enzyme.MetalEnzymes (important only)ZincCarbonic anhydrase, dehydrogenase (LDH, alcohol dehydrogenase), kinases, peptidases.MagnesiumCopperIronHexokinase, Enolase (chelated by NaF to prevent glycolysis in blood sample)Tyrosinase, Cytochrome oxidase, lysyl oxidaseCytochrome oxidase, catalase, peroxidiseMolybdenumXanthine oxidaseManganeseSuperoxide dismutaseCalciumLecithinase, lipaseMenkev kinky svndrome:-Dietary Cu is absorbed from GI tract, but cannot be transported to blood due to absence of an intra cellular copper binding ATPase.This results in defective cross linking of connective tissue.
Category:
Biochemistry
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