The disaccharide lactulose consists of a D-galactopyranose subunit and a D-fructofuranose subunit joined by a B-1,4'-glycosidic linkage. After treatment of lactulose with 1. excess CH3I/Ag20, 2. HCI/H20, the D-galactopyranose subunit was found to have one nonmethylated OH group, whereas the D-fructofuranose subunit had two. Draw the structure of a-lactulose.

The disaccharide lactulose consists of a D-galactopyranose subunit and a D-fructofuranose subunit joined by a B-1,4'-glycosidic linkage. After treatment of lactulose with 1. excess CH3I/Ag20, 2. HCI/H20, the D-galactopyranose subunit was found to have one nonmethylated OH group, whereas the D-fructofuranose subunit had two. Draw the structure of a-lactulose.

Introduction to General, Organic and Biochemistry

11th Edition

ISBN:9781285869759

Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres

Publisher:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres

Chapter20: Carbohydrates

Section: Chapter Questions

Problem 20.49P

See similar textbooks

Similar questions

The disaccharide lactulose consists of a d-galactopyranose subunit and a d-fructofuranose subunit joined by a β-1,4-glycosidic linkage. After treatmentof lactulose with 1. excess CH3I/Ag2O, 2. HCl/H2O, the d-galactopyranose subunit was found to have one nonmethylated OH group, whereas thed-fructofuranose subunit had two. Draw the structure of α-lactulose.
An unknown carbohydrate of formula C12H22O11 reacts with Tollens reagent to form asilver mirror. An a@glycosidase has no effect on the carbohydrate, but a b@galactosidasehydrolyzes it to d-galactose and d-mannose. When the carbohydrate is methylated (usingmethyl iodide and silver oxide) and then hydrolyzed with dilute HCl, the products are2,3,4,6-tetra-O-methylgalactose and 2,3,4-tri-O-methylmannose. Propose a structure forthis unknown carbohydrate
Deduce the structure of the disaccharide isomaltose from the following data.a. Hydrolysis yields D-glucose exclusively. b. Isomaltose is cleaved with α-glycosidase enzymes. c. Isomaltose is a reducing sugar. d. Methylation with excess CH3I, Ag2O and then hydrolysis with H3O+ forms two products:
An unknown reducing disaccharide is found to be unaffected by invertase enzymes. Treatment with an a@galactosidasecleaves the disaccharide to give one molecule of d-fructose and one molecule of d-galactose. When the disaccharideis treated with excess iodomethane and silver oxide and then hydrolyzed in dilute acid, the products are2,3,4,6-tetra-O-methylgalactose and 1,3,4-tri-O-methylfructose. Propose a structure for this disaccharide, and give itscomplete systematic name.
A nonapeptide released by globulins in the blood in response to a waspsting. Hydrolysis gives the following amino acids: 2 Arg, Gly, 2 Phe, 3 Pro, and Ser.Edman degradation gives phenylthiohydantoin of Arg. Cleavage with carboxypeptidase gives Arg. Partial hydrolysis gives the following di- and tripeptides: Phe-Ser, Pro-GlyPhe, Pro-Pro, Ser-Pro-Phe, Phe-Arg, and Arg-Pro. What is the amino acid sequence of this peptide?
Illustrate a glycosidic, peptide and a phospho-diester bond.
(a) Figure 23-2 shows that the degradation of d-glucose gives d-arabinose, an aldopentose.Arabinose is most stable in its furanose form. Draw d-arabinofuranose.(b) Ribose, the C2 epimer of arabinose, is most stable in its furanose form. Drawd-ribofuranose.
An unknown disaccharide gives a positive Tollens’ test. A glycosidase hydrolyzes it to d-galactose and d-mannose. When the disaccharide is treated with methyl iodide and Ag2O and then hydrolyzed with dilute HCl, the products are 2,3,4,6-tetra-O-methylgalactose and 2,3,4-tri-O-methylmannose. Propose a structure for the disaccharide.
Trehalose is a nonreducing disaccharide (C12H22O11) isolated from the poisonous mushroom Amanita muscaria. Treatment with an a@glucosidase converts trehalose to two molecules of glucose, but no reaction occurs when trehalose is treated with a b@glucosidase.When trehalose is methylated by dimethyl sulfate in mild base and then hydrolyzed,the only product is 2,3,4,6-tetra-O-methylglucose. Propose a complete structure andsystematic name for trehalose.
Consider the hydrolysis reactions of creatine phosphate and adenosine-5-monophosphate. Creatine Phosphate + H2O Creatine + HPi rG = 43.3 KJ/mol-rxn Adenosine-5-Honophosphate + H2O Adenosine + HPi rG = 9.2 KJ/mol-rxn Which of the following combinations produces a reaction that is product-favored at equilibrium: for creatine phosphate to transfer phosphate to adenosine or for adenosine-5-monophosphate to transfer phosphate to creatine?
0 Explain the relationship between transition-state analogs and abzymes.