This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Biochemistry
Which of the following does not contain uronic acid? 
Select and explain. 
A. Heparin, B. Keratin sulfate, C. Chondroitin sulfate, D. Dermatan sulfate
B: Keratin sulfate
Answer: B: Keratin sulfate 
Explanation: Glycosaminoglycans (mucopolysaccharides) are complex carbohydrates containing amino sugars and uronic acidsHeparin -Sulfated glucosamine +L iduronic acidKeratan sulfate - galactose + N-acetylglucosamineChondroitin sulfate - glucuronic acid + N-acetylglucosamineDermatan sulfate - L iduronic acid + N-acetylglucosamineReference: DM Vasudevan biochemistry 8th edition