sacharidy

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CARBOHYDRATES

• widely distributed in nature

structural
source of energy

• function

storage of energy

• classification

monosaccharides (1 unit)
oligosaccharides (2-10 units)
polysaccharides (gt 10 units)
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polyhydroxyaldehydes
aldoses

• chemically

polyhydroxyketones
ketoses
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Monosaccharides
aldoses
chemically
ketoses

• classification

Trioses Tetroses Pentoses Hexoses Heptoses Octoses
Number of carbon atoms
4

• contain asymmetric carbon atoms C

opticaly active

• 2n isomers (n number of C)

i.e.. hexoses 2416

• isomers two series D and L
• according to orientation of -H and -OH on last
  C ,
• based on orientation of the simplest aldose
• glyceraldehyde

• D- and L- isomers rotate the beam of
  plane-polarized light for the same angle, but
  opposite direction
• Equimolar mixture of D- and L- isomers has no
  optical activity - racemic mixture

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D-
L-
glyceradehyde
this is so called Fisher projection, figures
cannot be flipped!
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Epimers

• Pairs of monosaccharides different only in
• configuration on C adjacent to aldo/oxogroup

D-glucose
D-mannose
CH2OH
CH2OH
D-fructose
D-psicose
CH2OH
CH2OH
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Cyclic structure

• Acyclic structure cannot account for some of the
  properties

• cyclic hemiacetal forms exist

H
OH
OH
H


C
C
O
O
CH2OH
CH2OH
?-
?-
anomers
? hemiacetal hydroxyl of the same orientation
as reference C
? hemiacetal hydroxyl of the opposite
orientation then reference C
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• ??and ??anomers have different specific rotatory
  power gt reaching equilibrium is accompanied by
  changes in optical rotatory power of solution gt
  mutarotation

• most stable are rings with 5 and 6 members

most common in nature

• in accordance to oxygen containing heterocycles
  monosaccharides are called

with 5 atoms in cycle furanoses
with 6 atoms in cycle pyranoses
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Haworth projection

• more accurate for cyclic forms

• transcription from Fisher projection

• What was on right goes down
• What was on left goes up
• O is always up and right

H
OH
CH2OH
C
O
O
CH2OH

• D-forms CH2OH always up

• can be flipped and turned freely

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Haworth projection of ?-D-glucofuranose
Haworth projection of ?-D-glucopyranose
It is not planar!!!
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Saccharides isomerism - rewiev
STRUCTURE isomerism (CONSTITUTIONAL)

• same summary formula, different functional
  groups aldose ketose
• glucose fructose

EPIMERISM

• different orientation of hydroxyl on one C
• ( not reference)
• glucose mannose
• glucose galactose

OPTICAL isomerism (antipods, enantiomers)

• D- and L- isomerism
• mirror images
• D-glucose L-glucose

PYRANOSE-FURANOSE-ACYCLIC FORM

• in solutions in equilibrium
• ?-D-glucopyranose ?-D-glucofuranose
• acyclic glucose

ANOMERISM

• ??-D-glucopyranose ??-D-glucopyranose
• mutarotation

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Derivates

• deoxysaccharides

• one hydroxyl substituted by hydrogen
• deoxyribofuranose - part of DNA

H

• aminosaccharides

• hydroxyl on usualy second C substituted by -NH2
• glucosamine, galactosamine

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Reactions of monosaccharides

• oxidation

aldonic acid
gluconic a.
aldaric acid
monosaccharide
glucaric a.
D-glucose
alduronic acid
glucuronic a.
Could form cyclic inner esters - lactons
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• Oxidation of hemiacetal hydroxyl

• hemiacetal hydroxyl reduces
• Fehling / Cu 2/ and Tollens /Ag/ reagent

proof of monosaccharides
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Isomerization

• In alkaline solutions
• In organism catalyzed by enzymes

CH2-OH
ketose
O
CH-OH
endiol
CH-OH
CHO
aldose
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Esterification

• With acids
• Most reactive is hemiacetal hydroxyl
• In organism catalyzed by enzymes, mainly with
• trihydrogenphosphoric a.
• sulphuric a.
• GLC-6-P, FRU-1,6-bisphosphate
  galaktosamine-6-sulphate

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• By reactions of hemiacetal hydroxyl acetal
• GLYCOSIDIC BOND
• is formed

• with hemiacetal hydroxyl of other saccharide

nonreducing disaccharides

• with other then hemiacetal hydroxyl
• of other saccharide

redukucing disaccharides

• with nonsugar hydroxylem (alcohol, sterol,
  heterocycle)

O-glycosides
N-glycosides

• with amino(imino) group

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Oligosaccharides

• 2 to 10 monosaccharide units linked by
• O-glycosidic bond

• di-, tri-, tetrasaccharides etc.

• most important Disaccharides

reducing
classification
One hemiacetal hydroxyl is free, not involved in
bond
CH2OH
CH2OH
O
O
O
nonreducing
?-lactose
both hemiacetal hydroxyls form glycosidic bond
together
CH2OH
CH2OH
sucrose
O
O
O
CH2OH
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Disaccharides - types of links between glucose
units

• maltose ??(1-4) glu-glu

• isomaltose
• ??(1-6) glu-glu

• cellobiose
• ??(1-4) glu-glu

• trehalose
• ? (1-1) glu-glu

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Disaccharides

• Most important disaccharides

reducing

• maltose ??(1-4) glu-glu
• isomaltose ??(1-6) glu-glu
• cellobiose ??(1-4) glu-glu
• lactose ????????(1-4) gal-glu

nonreducing

• sucrose ????(1-2) glu-fru

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Polysaccharides

• more than 10 units

homopolysaccharides
only one type of units Glc - starch, glycogen,
cellulose Gal - agar Fru - inulin

• classification

heteropolysaccharides
more types of units
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• most important homopolysaccharides of glucose -
• GLUCANS

• starch

amylose - nonbranching
? ( 1-4 )
helix insoluble in cold waterstained blue by
iodine
amylopectin - branched
soluble in cold waterstained red-brown by iodine

• glycogen similar to amylopectin
• more highly branched
• not stained by iodine storage polysaccharide
  of animals, muscles, liver
• cleaved by alpha amylase

? ( 1- 4 )

• cellulose

firm, insoluble, chemically very resistant chief
constituent of plants framework cotton
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Other homopolysaccharides

• inulin
• storage polysaccharide in tubers and roots of
  dahlias, artichokes, dandelions
• In medicine used for physiologic investigations
  of renal functions - determination of the rate of
  glomerular filtration - clearance of inulin
• agar gal -gal
• sea algaefood, culture media, imprinting
  materials
• chitin
• N-acetyl-D-glucosemin ? ( 1- 4 ) structural
  polysaccharide of invertebrates (in complex with
  proteins and/or CaCO3)
• pectin
• D-galakturonic acid a (1-4)
• small fruits, plants
• forms jelly

fru - fru ? ( 1- 2 )
? ( 1- 4 ) a ? ( 1- 3 )
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ALGINATES
Heteropolysaccharides

• Salts of alginic acid - polyuronide made up of a
  sequence of two uronic acid residues
• b-D-mannuronic a.
• a-L-guluronic a.
• Residues distributed irregularly
• form blocks of up to twenty units
• depends on the species of seaweed
• determine the physical properties
• Imprinting materials
• less accurate than agar
• cheap, tasty

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Heteropolysaccharides
GLYCOSAMINOGLYCANS common structure N-acetylhexo
samine (glucosamine, galaktosamine) uronic
acid (glucuronic, iduronic)
Always in complex with proteins -
proteoglycans Part of inercellular matrix (bone,
cartilage, ligament)
hyaluronic a. N-acetylglucosamine, glucuronic
a. chondoitinsulphate N-acetylgalactosaminsulphate
, glucuronic a. dermatansulphate
N-acetylgalactosaminsulphate, iduronic
a. heparin glucosaminsulphate, both acids
(sulphated)
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Proteoglycans

• Ground of packing substance
• Molecule resembles forrest - proteoglycan
  subunits are noncovalently bond to molecule of
  hyaluronic acid
• Proteoglycan subunits
• protein core
• covalently bond glycosaminoglycans
  (mucopolysaccharides - keratansulphate,
  chondroitinsulphate)
• Hold large quantities of water, cushioning and
  lubrication of other structures
• Glycosylation in ER

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Sialic acids N- od O-acyl derivates of neuraminic
acid, which is product of aldol condensation
of MANNOSAMINE and PYRUVATE
Part of glycoproteins and glycolipids
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That is the end, friends!