Which of the following mucopolysaccharide does not contain an acidic sugar?
Ans: B (Keratan sulfate) Ref: Lippincott Illustrated Review Biochemistry, 6th edition, pg: 159 Explanation:GlycosaminoglycansCompositionKey featuresChondroitin sulfateGlucuronic acid + N- acetyl galactosamine sulfateMost abundant GAG in the bodyDermatan sulfateIduronic acid + N- acetyigalactos amine Keratan sulfateGalactose + N- acetyl glucosamineNo acidic sugarsHeparan sulfateSame as heparin(minimal acetylation) HeparinGlucuronic acid + glucosamineOnly intracellular GAG in the body and most powerful anticoagulantHyaluronic acidGlucuronic acid + N- acetyl glucosamineOnly GAG not limited to animals. Found in bacteria GlycosaminoglycanMainlocalizationSulfated?Attached to protein?Acidicsugarpresent?Chondroitin sulfateCartilageTendonLigamentYesYesYesDermatan sulfateSkinBlood vessels Heart valvesYesYesYesKeratan sulfateCartilageCorneaYesYeaNoHeparan sulfateBasement membrane Cell surfaceYesYesYesHeparinMast cells (Anticoagulant)YesYesYesHyaluronic acidJoints Cartilage Umbilical cord Vitreous humor (eve)NoNoYes GlycosaminoglycansGlycoproteins1. Primarily CHOPrimarily protein (mucin is an exception)2. CHO chains are always negatively charged and usually sulfatedCHO chains may be negatively charged but are unsulfated3, Long straight CHO chains (unbranched) containing repeating disaccharide unitsShort CHO chains, branched with no repeating disaccharide units4. Distinctive sugars include glucuronic/iduronic acids and xyloseDistinctive sugars include Mannose, sialic acid and fucose5. Support cellular and fibrous components of tissues and mediate cell-cell signaling and adhesionCell-surface recognition and antigenecity. components of ECM, mucins and globular proteins in plasma
Chondroitin sulfate
Keratan sulfate
Dermatan sulfate
Heparin
Miscellaneous (Structure & Function of Proteins)