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Part IV: Carbohydrates Biological Chemistry I: Nucleic Acids & Carbohydrates Prof. Helma Wennemers
Part IV: Carbohydrates
Biological Chemistry I: Nucleic Acids & Carbohydrates
Prof. Helma Wennemers
• Occurrence and Importance in Nature • Nomenclature – anomeric effect • Structure
• Synthesis – Glycosylation – Protecting Groups • Functions
Carbohydrates in Nature
15000 years ago (Spider cave, Valencia)
Structural Energy storage (Glycolysis)
Cellulose Chitin Amylose
OOHO
OH
OHO
O HOOH
OH
n
OOHO
HO
OH
OHO
OH
OH
n
O
poly α(1-4)-glucopyranose poly β(1-4)-glucopyranose
Carbohydrates in Nature (cont.) Molecular Recognition
Neomycin
Blood type determinants Streptomycin
Antibiotics
O A
B AB
O OH
OHOH
H3C
O
OOR
OHHOOHO
HOHOO
OH
O OH
OHOH
H3C
O
OOR
OHHOOHO
HOAcHNO
OH
A B
Carbohydrates in Nature (cont.) Molecular Recognition Leucozyte adhesion upon inflammation!
Sialyl Lewis x (sLex) - ligand for selectins
OH
O
HOAcHN
CO2HHO OH
OO
OH OH
OH
O
OO
OHOR
NHAc
O
OH
H3C
OHOH
N-Acetyl Neuraminsäure Galaktose N-Acetyl glukose
Fucose
Emil Fischer (1852 – 1919)
.....studied with Adolf von Baeyer earned his PhD on phthalein dyes 1874 – Assistant instructor - discovered the first hydrazine base, phenylhydrazine 1881 – Professor of Chemistry at the University of Erlangen Gastritis problems force leave of absence and caused him to refuse a tempting offer to follow Victor Meyer at the ETH Zurich 1888 – Professor of Chemistry at the University of Würzburg 1892 – Chair of Chemistry at the University of Berlin 1902 – Nobel Prize in Chemistry for his work on sugar and purine syntheses
....according to his father: „Der Junge ist zum Kaufmann zu dumm, er soll studieren“
Emil Fischer. Aus meinem Leben. Berlin, 1922, S. 45 (Buch auf zeno.org)
„In its early youth organic chemistry was so closely connected with biology. I do consider it not only possible but desirable, that the close connexion of chemistry and biology [....] should be reestablished, as the great chemical secrets of life are only to be unveiled by cooperative work.“
Emil Fischer, Faraday Lecture: Synthetic Chemistry in its Relation to Biology, J. Chem. Soc. 1907, 1749.
Emil Fischer (1852 – 1919)
http://www.nobel.se/chemistry/laureates/1902/fischer-bio.html Kunz, H. „Emil Fischer - Unequalled Classicist, Master of Organic Chemistry Research, and Inspired Trailblazer of Biological Chemistry“ Angew. Chem. Int. Ed.2002, 41, 4439-4451
OOH
OH
CO2HAcNHHO OH
OH
Most Common Monosaccharides in Mammals
HOO
HO
CO2H
OH
HO
HOO
AcNH
OH
OH
HO
HOO
HO
OH
OH
HOHO
O
HO
OHHO
OH
HOO
HO OH
HO O OH
OHOH
H3COH
HOO
AcNH
OHHO
OH
Glucose (Glc) Galactose (Gal) Mannose (Man)
Xylose (Xyl) Fucose (Fuc) Glucuronic acid (GluA)
N-Acetylgalactosamine (GlcNAc)
N-Acetylglucosamine (GalNAc)
N-Acetylneuraminic acid Sialic acid (NANA)
HOO
OH
OH
HOOH
Carbohydrates – Nomenclature
Fuc α-(1→2)Gal β-(1→3)GalNAc β-(1→3)Gal α-(1→4)Gal β-(1→4)Glc
O OH
OHOH
H3C
O
OO
OHHO
HOO
NHAcO
OHHOO
HO
OHHO
O
OH
OHO
HO O
OH
OH
HOO
OH
α α
β
β β reducing end
non-reducing end
Cellulose β(1->4) glycosidic linkages
www.biologie.uni-hamburg.de/ b-online/e26/26a.htm courses.cm.utexas.edu/.../ ch339k/overheads-2.htm
Carbohydrates – Structure
OOHO
OH
OHO
O HOOH
OH
n
Amylose and Amylopectin Amylose Amylopectin
additionally α(1->6) branches
Carbohydrates – Structure (cont.) α(1->4) glycosidic linkages
OOHO
HO
OH
OHO
OH
OH
n
O
Glycoproteins
N-linked – via Asn
O-linked! via Ser or Thr
anti freeze glycopeptide
NH
O
O
HOO
AcNH
OH
NH
HOO
AcNH
OH
OOHOOH
O
HOO
HOHO
O
HOO
AcNH
OHO
O
O OH
OHOH
H3C
O
O
OHHO
HOHO
O
AcNH
OHO O
OH
OHHO
O
HOO
HOHO
O
HOO
AcNH
OHO
O
O OH
OHOH
H3C
O
O
OHHO
HOHO
O
AcNH
OHO O
OH
OHHO
O
H-type 2 Blood Group Determinant
Lactosamine Spacer
High Mannose Region Chitobiose
NH
O
HN
NH
O
O
OO
AcNH
OHHO
O
HOO
AcNH
OHHO
n
Glycolipids
HOO
HO
OHHO
ONH
HOO 5
nn = 6,8,10,...
HOO
HO
OH
ONH
HOO 5
nn = 6,8,10,...
HO
e.g. Cerebrosides (belong to the group of glycosphingolipids)
in nerve cells
in liver, and spleen (Glc) tissue
