The enzyme Endoglycosidase H (Endo-β-N-acetylglucosaminidase H, (EC 3.2.1.96) is a highly specific endoglycosidase which cleaves asparagine-linked mannose rich oligosaccharides, but not highly processed complex oligosaccharides from glycoproteins. This article is about the Enzyme Commission codes For the European Commission system for coding chemicals see EC-No. An Endoglycosidase is an Enzyme that releases Oligosaccharides from Glycoproteins or Glycolipids Or it merely cleaves polysacharride chains between Asparagine (abbreviated as Asn or N; Asx or B represent either asparagine or Aspartic acid) is one of the 20 most common natural An oligosaccharide is a Saccharide polymer containing a small number (typically three to ten of component sugars also known as Simple sugars. Not to be confused with Peptidoglycan. Glycoproteins are proteins that contain Oligosaccharide chains ( Glycans) covalently attached Endoglycosidase H cleaves the bond between two N-acetylglucosamine (GlcNAc) subunits directly proximal to the asparagine residue. N-Acetylglucosamine ( N-Acetyl-D-Glucosamine, or GlcNAc, or NAG) is a Monosaccharide derivative of Glucose. [1]
Biochemical Applications
Endoglycosidase H (Endo H) is commonly used by cell biologists to monitor posttranslational modification in the Golgi apparatus. Posttranslational modification (PTM is the chemical modification of a Protein after its translation. The Golgi apparatus (also called the Most proteins destined for the cell surface are transcribed by ribosomes in the rough endoplasmic reticulum (ER) and translocated into the Golgi. Transcription is the synthesis of RNA under the direction of DNA Ribosomes ( from ribo nucleic acid and "Greek soma ( meaning body") are complexes of RNA and Protein that The endoplasmic reticulum (Greek endo = "within" (prefix plásma = "formed entity" Latin reticulum = "little net" or ER, is an Organelle Upon entering the ER a molecule containing 11 sugar subunits is linked en bloc to an asparagine in a selective manner by the enzyme oligosaccharyl transferase. Oligosaccharyltransferase or OST ( is a Membrane protein complex that transfers a 14- Sugar Oligosaccharide from Dolichol It is this oligosaccharide molecule which is modified by a series of enzymes as the protein moves through the different compartments of the Golgi apparatus. Endoglycosidase H is able to cleave each structure of this oligosaccharide as it is processed until the enzyme Golgi alpha-mannosidase II removes two mannose subunits. Golgi α-mannosidase II is a key enzyme involved in N-linked Glycan processing Mannose is a Sugar Monomer of the Hexose series of Carbohydrates Metabolism Mannose enters the carbohydrate Metabolism Since all later oligosaccharide structures are resistant to Endo H cleavage the enzyme is widely used to report the extent of oligosaccharide processing a protein of interest has undergone. [2]
External links
IUBMB Enzyme Nomenclature - EC 3.2.1.96
References
- ^ Endoglycosidase H, Bioresearch Online
- ^ Alberts et al. (2002) Molecular Biology of the Cell, Fourth Edition ISBN 0815340729