CARBOHYDRATESo a.k.a. SACCHARIDESo (CH2O)n

n – number of atoms in a unit CH2O – hydrated carbon

o Major energy cycle of life

FUNCTION:1. energy storage/generation2. structural3. molecular recognition

CLASSIFICATION:1. MONOSACCHARIDE – one polymer2. OLIGOSACCHARIDE – few polymer3. POLYSACCHARIDE – many polymer

MONOSACCHARIDE – named by bases on the number of carbon atoms

*simplest form: TRIOSE*more biologically important: HEXOSE & PENTOSE

CLASSIFICATION OF MONOSACCHARIDESA. ACCORDING TO THE GROUP ATTACHING TO IT:

1. ALDOSE Aldehyde group (CHO) (-ose)

2. KETOSE Keto group (C=O) (-ulose) except FRUCTOSE

B. ACCORDING TO THE NUMBERING1. ALDOSE – C1 is attached to the aldehyde group2. KETOSE – C1 closest to the keto group

*ALDOSES are more biologically important

STRUCTURES OF MONOSACCHARIDES:o ISOMERS – same formula but different structureo EPIMERS – isomers with structures varying in

one position of carbono C4 – GLUCOSE & GALACTOSEo C2 – GLUCOSE & MANNOSE

o ENANTIOMERS – isomers that are mirror images of each other

-- have chiral carbos that can produce D light

*natural occurring carbohydrate in D configurationo DIASTEREOISOMERS – possesses more than 1

chiral carbon -- not mirror imagesEx. D/L erythrose; D/L threose

o ANOMERS – isomers that differ in position -- 5 or 6 carbons (ring structures) -- internal hemiacetal formation

*INTERNAL HEMIACETAL FORMATION – process of ring formation

2 WAYS OF FORMING A RING:o Reaction of C1 & C5 via HYDROXYLATION

(PYRANOSE RING *5C & 1 O2)o Reaction of C1 & C4 (FURANOSE RING) 5

membered ring

CYCLIZATIONo Produces asymmetric centric carbon –

ANOMERICo OH & H change (interchange)o C1 – farthest to the right (in ring)o Can produce 2 or more anomeric configuration

(alpha and beta)

MUTAROTATIONo Alpha can be Beta and vice versao Change of configurationo ALPHA – OH is below Ho BETA – OH is above H

WAYS TO WRITE CARBOHYDRATES:o FISHER PROJECTION – linearo HAWORTH PROJECTION – ring

IMPORTANT MONOSACCHARIDES:o GLUCOSE (C6H12O6)

Most common HEXOSE Found in STARCH, CELLULOSE &

GLYCOGEN Found in VEGETABLES, FRUITS, CORN

SYRUP & HONEY Found in DISACCHARIDES, SUCROSE,

LACTOSE & MALTOSEo D-GALACTOSE (C6H12O6)

C4 EPIMER Obtained from Lactose; disaccharide An aldohexose not found free in nature Attach to glucose as lactose

o FRUCTOSE (C6H12O6) Ketohexose/ketose Sweetest carbohydrate Found in fruits and honey Converted to glucose in the body

DERIVATIONS OF MONOSACCHARIDES:*modified; plays important roleo PHOSPHATE ESTERS

PHOSPHORYLATION OF MONOSACCHARIDES

ATP, AMP, nucleic acid

o ACIDS & LACTONES OXIDATION OF

MONOSACCHARIDES Produces GLUCORONIC

ACIDo ALDITOLS

REDUCTION OF MONOSACCHARIDES Produces SORBITOLS

o AMINO SUGARS

Sugar with amino group Monosaccharide with amino groups Ex. GLUCOSAMINE – better cartilage

OLIGOSACCHARIDE – linked monosaccharides

GLYCOSIDIC BONDo Links monosaccharideso Formed by removing water

*DISACCHARIDE GROUP – important groupLACTOSE – formed by GLUCOSE & GALACTOSE

NAMING OLIGOSACCHARIDES:o Non-reducing sugars firsto From left-righto PREFIX: ALPHA or BETAo SUFFIX: pyranose, furanoseo –cylo LINKAGE: (1,4) *pyranocyl, furanocyl

1 mono + 1mono = disaccharidesEx. Glucose + glucose = Maltose Glucose + galactose = Lactose

COMMON DISACCHARIDES:GLUCOSE + FRUCTOSE = SUCROSE(1,4) GLUCOSE + GLUCOSE = MALTOSEGLUCOSE + GALACTOSE = LACTOSE(1,4) GLUCOSE + GLUCOSE = CELLOBIOSE(1,6) GLUCOSE + (1,4) GLUCOSE = ISOMALTOSE

POLYSACCHARIDE o Structuralo Catalyzed by enzymeso Polymers of saccharide linked by glycosidic bondo Storage form of sugar ex. Glycogen & starch

STORAGE:o AMYLOSE

Polysaccharide; storage form of sugar in plant (starch)

Saccharide link by ALPHA-1,4-GLYCOSILIC BOND

Polysaccharide arrange in linear manner linked by ALPHA-1,4-GLYCOSIDIC BOND

Found in potato & starcho AMYLOPECTIN

Polysaccharide arranged in branch manner or structure linked by ALPHA-1,4-GLYCOSIDIC BOND

Branch structure ALPHA-1,6-GLYCOSIDIC BOND

Found in starch

o GLYCOGEN Polysaccharide found in LIVER & MUSCLE Storage form of glucose in body Branched: formed by Glycosidic Bond:

ALPHA-1,4 & ALPHA-1,6 Not found in potato

GLUCOSEo High osmotic pressureo Small molecule, GLUCOGEN – semi-soluble (do

not change osmotic pressure, ready to use when metabolism is acquired) GLUCOGEN -> GLUCOSE

STRUCTURAL:o CELLULOSE

Polysaccharide found in plants Linked by BETA-1,4 glycosidic bond α-glycosidase – can only break α bonds;

found in man β -glycosidase – can only break β bonds;

found in cows, goats, etc. cow’s intestinal tract has bacteria that

produce BETA glycosidaseo CHITIN – polysaccharide found in shell,

invertebrate, insect and fungio PEPTIDOGLYCAN –polysaccharide in the cell

wall of bacteriao GLYCOSAMINOGLYCAN – they form the matrix

of connective tissue

MOLECULAR IDENTIFICATION:GLYCOPROTEIN – protein linked to sugar/carbohydrate

2 FORMS:o O– LINKED – sugar is attached to protein

through SERINE/ THREONINEo N- LINKED – sugar is attached to protein through

ASPARGINE

*ER – produce proteins

* GOLGI COMPLEX – modifies proteins

FUNCTION OF N-LINKEDo Identify cell surface (IMMUNOGLOBULIN)o TIME CLOCK – signals for digestion (phagocytic

cells)o INTRACELLULAR TRANSPORT SIGNAL

(labeling proteins)

FUNCTION OF O-LINKEDo Anti-freeze substanceo Increases viscosity of secretion *MUCIN*o INTRACELLULAR TRANSPORT SIGNAL

-Rosette Go 082108