Carbohydrate

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Carbohydrate

• Aulanniam
• Laboratory of Biochemistry
• Brawijaya University

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Six Classes of Nutrients

1. Carbohydrate
2. Protein
3. Fat
4. Vitamins
5. Minerals
6. Water

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Carbohydrates and Relation to Health

• Dietary fiber and prevention of chronic diseases
• Carbohydrates and dental health
• Carbohydrates and diabetes
• Carbohydrates and weight loss???

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Carbohydrates and Prevention of Chronic
DiseasesHealth Benefits of Fiber

• Reduce the risk of
• Heart disease
• Diabetes
• Diverticular disease (gastrointestinal / GI)
• Other
• Relieves Constipation
• Hemorrhoids
• Lowers the GI/GL
• Makes you feel full

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Complex Carbohydrates

• Starch
• digestible plant polysaccharide
• Fiber
• indigestible polysaccharide residues of food
• Cannot be broken down by human digestive enzymes
• some broken down by bacteria in the digestive
  tract
• few, if any, calories because not digested
• Examples cellulose, hemicellulose, pectin, gums

Polysaccharide long chain of 10 or more glucose
molecules linked together the chains can be
straight or branched another term for complex
carbohydrates
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Dietary Fiber

• Components of the cell walls of plants
• cereal grains, fruits, vegetables
• Polymer of monosaccharides
• Human digestive enzymes cannot break down
• Cellulose 3000 glucose

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Dietary Fiber - Two groups

• Insoluble
• fibers that mostly do not dissolve in water
• not digested by bacteria in the large intestine
• Soluble
• fibers that either dissolve or swell in water or
• are metabolized by bacteria in the large
  intestines

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Fiber Sources
Soluble Fiber - Heart Insoluble Fiber GI tract
? Oatmeal ? Nuts and seeds ? Legumes dried peas beans ? Fruits apples pears ? Whole grains ? Wheat bran ? Vegetables carrots celery
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Degree of polymerization

• Monosaccharides
• Storage, energy modules, metabolic intermediates
• Disaccharides, trisaccharides
• Storage
• Oligosaccharides
• Molecular Recognition
• Polysaccharides
• Structure, storage

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Fisher Projectionsof chiral monosaccharides

• Next-to-bottom carbon hydroxyl extends to the
  right --- a D sugar cf. with L amino acid

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fig 9-3a
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fig 9-3b
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Hemiacetal/-ketal structures of monosaccharides

• Reaction of an aldehyde or ketone with an alcohol
• favorable intramolecular reaction

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fig 9-5
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Intramolecular hemiacetals/ketals of
monosaccharides are RINGS
stereo
chair
open chain
Haworth
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Anomers

• Sugars that vary in configuration about the
  anomeric (aldehydic or ketonic) carbon
• Convention ? hydroxyl down,
• ? hydroxyl up

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fig 9-6
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Fig 9-7
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Hexose derivatives

• Amino sugars
• Acetamido sugars
• Deoxy sugars
• Fucose, rhamnose, abequose
• Other glycosidic additives
• Lactic acid
• Oxidized sugars
• Sugar phosphates

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Fig 9-9
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Reducing sugars

• Aldehydes are oxidized by mild agents
• Cu2 aldehyde (or ?-hydroxyketone) ? Cu
  acid
• Disaccharides react more slowly

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Fig 9-10
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Disaccharides

• Glycosidic linkage
• Acetal (or ketal) formed. 2nd monosaccharide
  acts as an alcohol

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Fig 9-5 (repeat)
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• Reducing
• one anomeric C not glycosidically linked
• Nonreducing
• Both anomeric Cs linked (fructose, trehalose)

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Disaccharide nomenclature

• Nonreducing end on left
• Linkage (n?m)-
• Reducing end
• Note that nonreducing end configuration is fixed
• Reducing end can mutarotate, thus 1st component
  given as ?- or ?-, 2nd ambiguous (next slide)

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Fig 9-11
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Table 9-1
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Important disaccharides

• Maltose
• Lactose
• Sucrose
• Trehalose

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Fig 9-12
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Table 9-2
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Storage polysaccharides

• Plants
• Starch
• Amylose llinear polyglucose, ?-1,4 linked
  (?-D-glucopyranosyl-(1?4)-), M 106
• Amylopectin polyglucose, ?-1,4 linked, ?-1,6
  branched 1 per 24-30, M 108
• Animals
• Glycogen
• polyglucose, ?-1,4 linked, ?-1,6 branched 1 per
  24-30, M 106

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Fig 9-15 b
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Fig 9-14
0.10 ?m
1.0 ?m
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fig 9-15
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Structural Polysaccharides

• Plants
• Cellulose linear polyglucose
• ? 1,4 linked
• M 106
• Certain exoskeletons
• Chitin linear poly(N-acetyl-D-glucosamine)
• ? 1,4 linked

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Fig 9-17a and 9-18
Cellulose
Chitin
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Structural polysaccharides, cont

• Bacterial cell walls peptidoglycans
• Extracellular matrix of multicellular animals -
  glycosaminoglycans

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Fig 9-19
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Fig 9-20
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Sugar-protein and sugar-lipid conjugates

• Glycoconjugates
• Proteoglycans
• Glycosaminoglycans bound to proteins
• Glycoproteins
• Oligosaccharides bound to proteins
• Glycolipids
• Oligosaccharides bound to lipids (heads of
  membrane lipids)

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Fig 9-29
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Fig 9-27
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2. Carbohydrates and Dental HealthDental Caries
(Cavities)
Cavities
Bacterial Sugars

• MECHANISM
• Bacterial acid dissolves enamel
• Carbohydrate serves as food for bacteria
• Plaque on teeth sugars stay in but acids dont
  go out
• CARIOGENIC FOOD FACTORS
• Fermentable contains sugars
• Sticky
• Stays in mouth a long time (think taffy)

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3. Carbohydrates and Diabetes

• Diabetes An inability to regulate blood glucose
  levels
• A disease in which an individual does not produce
  or properly use insulin

• Results in
• abnormally high levels of glucose in blood
• Because of
• lack or ineffectiveness of insulin
• hormone that is needed to convert sugar, starches
  and other food into energy needed for daily life
• the true cause continues to be a mystery,
• although both genetics and environmental factors
• such as obesity and lack of exercise play roles

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Type I vs. Type II Diabetes
Type 1 Insulin Dependent
Type 2 Non- Insulin Dependent
Incidence

• 5-10 of cases
• Pancreas unable to make insulin to meet needs
• Genetic predisposition environmental factors
• Insulin injections
• Dietary Intervention
• Reduce the amount of simple sugars
• Eat foods w/ dietary fiber
• Person will lose weight

• 90-95 of cases
• Maybe insufficient insulin or cells maybe
  unresponsive to insulin
• Genetic predisposition obesity
• Dietary intervention
• Weight loss intervention
• Person is always hungry
• Increase in obesity

Insulin
Risk factor
Treatment
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Carbohydrates role in blood glucose
Glycemic Index

• A numerical system
• Measures extent of rise in circulating blood
  sugar a carbohydrate triggers
• GI number, blood sugar response

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Glycemic Index

• estimate of how quickly food affects your blood
  sugar

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Glycemic Index

• High GI gt 70 potatoes, white bread
• Low GI lt 55 pasta, whole grain bread
• Not just about individual foods
• its about our diet

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Factors Influencing GI

1. Biochemical structure of the carbohydrate
2. Absorption process
3. Size of the food particle
4. Contents and timing of the previous meal
5. Co-ingestion of fat, fiber, or protein

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Carbohydrates and Weight Loss??

• Low carb diets
• Diet and low calorie foods

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http//www.sigmaaldrich.com/img/assets/ 4202/sigma
_metabolic_path-new.pdf
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