In N-linked glycoproteins, to which of the following amino acids, oligosaccharides are covalently attached?
Correct Answer: Asparagine
Description: Ans: b) Asparagine Glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbones. Glycoproteins, where N-glycosidic linkage takes place between amide nitrogen of Asparagine, are called as N- linked glycoproteins Types of glycoproteins: 1. N-linked glycoproteins 2. O-linked glycoproteins 3. GPI-anchored proteins O-linked glycoproteins and N-linked glycoproteins are major classes of glycoproteins. O-linked glycoprotein: glycoproteins where O- glycosylation occurs at Serine >> threonine residues N-linked glycoproteins: glycoproteins where N- glycosidic linkage takes place between amide nitrogen of Asparagine. EXTRA EDGE: Periodic acid Schiff (PAS) reagent helps to detect glycoproteins as pink bands after electrophoretic separation. It is a staining method used to detect polysaccharides such as glycogen, and mucosubstances such as glycoproteins, glycolipids, and mucins in tissues. PAS staining can be used to facilitate the diagnosis of several medical conditions: Glycogen storage diseases (versus other storage disorders) Adenocarcinomas, which often secrete neutral mucins Staining of macrophages in Whipple's disease Useful in the diagnosis of A1-antitrypsin deficiency if peripoal liver hepatocytes stain positive.
Category:
Biochemistry
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now