Agricultural ProductStarchLipid

Organic waste

Carbohydrate producing plant• Corn• Rice• Sago

• Tuber crop

Annual lipid producing plant

1. Peanut Arachis hypogea

2. Winged bean Psophocorpus tetragonolobus3. Soybean Glycine max

4. Corn Zea mays

5. Rice Oryza sativa

6. Sesame Sesamum indicum

7. Sunflower Helianthus annuus

Perrenial lipid producing plant

1. Castor Ricinus communis

2. Jatropa Jatropa curcas

3. Kapok Ceiba petandra

4. Rubber Hevea brasiliensis

5. Coconut Cocos nucifera

6. Moringa Moringa oleifera

7. Nutsege Aleurites mollucana

8. Kusambi Sleichera trijuga

9. Oil palm Elais guineensis

10. Avocado Persea gratissima

11. Cacao Theobroma cacao

12. Kepoh Sterculia foetida

13. Nyamplung Callophylum inophylum

14. Randu Bombax malabaricum

15. Tengkawang Shorea stenoptera

CarbohydrateA group of organic compounds that includes sugars and related

compounds

Sugar

1. Compounds with between 3 – 7 carbon atoms having many hydroxyl (alcohol) groups and either a ketone group or an aldehyde group

2. A convenient source of energy

3. Raw material for many chemical syntheses

4. Water soluble

Sugar

Triose GlyceraldehydeDihydroxyacetone

Tetroses ErythroseThreose

Pentose ArabinoseRiboseXylose

Hexose GlucoseFructoseGalactoseMannose

DisaccharidesTwo molecules of a simple sugar linked together

Sucrose

Lactose

Cellobiose

Maltose

PolysaccharidesLong chain of simple sugar

Two main functions:

1. Storage

2. Structure

Storage carbohydrateA way of storing nutrients for future needs

To cover periods when its ability to supply nutrients from photosynthesis is inadequate (during growth and regeneration)

The commonest are starches and starch like materials

It is stored at seeds or tuber

StarchA mixture of two different types of molecules:

1. amylose (a long chain of glucose joint by α-1,4 linkages)

2. amylopectin (a mixture of α-1,4 links with occasionally α-1,6 branches

In general, amylopection accounts for about 70% of starch

Starch from different source vary in ratio of amylose and amylopectin

Plants use glyoxylate cycle to convert lipids to carbohydrates

Plants use glyoxylate cycle to convert lipids to carbohydrates

GlcoGlco

Glco

Glco

Glco

Starch synthase

Xa

Xb

PP

PPGlco

Glco

Glco

GlcoGlco

PPGlco

Glco

Glco

PPGlco

GlcoGlco

Glco

Glco

Glco

PPGlco

PPGlco

Glco

Glco

Glco

Glco

Glco

Starch biosynthesis is growing from reducing end

Sucrose biosynthesis

• Sucrose is synthesized in cytosol by sucrose 6-phosphate synthase and sucrose 6-

phosphate phosphatase.

Sucrose 6-phosphate synthase is also regulated

Sucrose 6-phosphate synthase is regulate by

phosphorylation/dephosphorylation.Sucrose 6-

phosphate synthase

P

SPS kinase

SPS PPase

G 6-P Pi

Starch biosynthesis is regulated by ADP-glucose pyrophosphorylase

Lipid

Any of a group of organic compounds consisting of the fats and other substances of similar properties,

insoluble in water but soluble in fats solvent and alcoholStructurally diverse range of compounds which have 2

features in common: (1). Their presence in living organism and (2). Their general solubility in organic

solvent and insolubility in water It is characterized by the presence of fatty acid moieties

and which are best described as acyl lipids

Plant lipid

Most plants do not store large quantities of lipids, with the exception of some oilseeds

Most lipid in plants have structural role as component of membranes and are synthesized in each cells

Plant do not transport fatty and complex lipids between their tissue

The most important plant tissues involved in lipid biosynthesis are the seeds

Seeds produce large quantities of triacylglicerols Large agricultural and food industry has developed around the

extraction and utilization of lipids from oil seeds

Acyl LipidNeutral

More readily soluble in non polar hydrocarbon solvents such as light petroleum and benzene

Glycerides (triacylglycerols): trihydroxy alcohol glycerolsWaxes (fatty acid esters of long chain monohydroxy alcohols)

PolarMuch more soluble in polar solvents like ethanol

Phospholipids (diester of orthophosphoric acids)Glycolipids (one or more monosaccharide residues)

Acyl Lipid StructureMajor fatty acids

All saturated and unsaturated monocarboxylic acids with an unbranched, even numbered carbon chain

Palmitic, oleic and linoleic acids often predominateIn general, saturated acids are less abundant than unsaturated acid

Minor fatty acidsTwo main categories: (1). Saturated and the cis-mono unsaturated acids,

(2)polyunsaturated acids

Unusual fatty acidsFatty acids which have (1) non-conjugated double bonds which are trans or in an

unusual position, (2). Conjugated double bond systems, (3). Allenic double bonds, (4). triple bonds, (5). Oxygen functions and (6). Branched chain

The Major Plant Fatty Acids

Common name Symbol Structure

Lauric acid 12:0 CH3-(CH2)10-COOH

Myristic acid 14:0 CH3-(CH2)12-COOH

Palmitic acid 16:0 CH3-(CH2)14-COOH

Stearic acid 18:0 CH3-(CH2)16-COOH

Oleic acid 18:1 (9c) CH3-(CH2)7-CH=CH-(CH2)7-COOH

Linoleic acid 18:2(9c,12c)

CH3-(CH2)4-(CH2-CH=CH)2-(CH2)6-COOH

α-linoleic acid 18:3(9c,12c,15c)

CH3-(CH2)-(CH2-CH=CH)3-(CH2)7-COOH

Glycerides Fatty acid esters of trihydroxy alcohol

The fast majorities in nature have all 3 of glycerol hydroxy groups esterified with fatty acids and are called triglycerides

(triacylglycerols) They are the main constituents of natural fats and oil Food reserves in seeds and/or fleshy part of fruit

Serve as carbon store in seeds required for biosynthesis processes during seed germination not as an energy store

Triacylglycerols have an advantage over carbohydrate as storage compounds due to their weight/carbon content ratio is much

lower

Glycerides Carbon in the seed as fat requires less than half the weight as

when stored as starch Low weight is advantageous for seed dispersal

They are deposited in oil bodies which consist of oil droplet which are surrounded by a lipid monolayer

Synthesis of glycerides occur in ER membrane Apart from their obvious value to the plants, they are of

enormous commercial importance

Phospholipid Glycerophospholipids Sphingophospholipids

Glycolipid Galactosyldiglycerides

Cerebrosides sulpholipids

LIPID BIOSYNTHESIS

• Fatty acid biosynthesis-basic fundamentals• Fatty acid biosynthesis-elongation and

desaturation• Triacylglycerols

Fatty Acid Biosynthesis

CytosolRequires NADPHAcyl carrier protein

D-isomerCO2 activation

Keto saturated

MitochondriaNADH, FADH2

CoA L-isomerNo CO2

Saturated keto

Beta OxidationSynthesis

Rule

Fatty acid biosynthesis is a stepwise assemblyof acetyl-CoA units (mostly as malonyl-CoA)

ending with palmitate (C16 saturated)

Fatty acid biosynthesis is a stepwise assemblyof acetyl-CoA units (mostly as malonyl-CoA)

ending with palmitate (C16 saturated)

Activation

Elongation

Termination

3 Phases

CH3C~SCoA

O

ACTIVATION

-OOC-CH2C~SCoA

O

HCO3-

active carbon

Acetyl-CoA carboxylase

ATP

ADP + Pi

1. Acetate is the basic two-carbon unit from which fatty acids are synthesis

2. It must be first converted to acetyl-CoA

3. Acetyl-CoA is produced in large quantities from pyruvate in mitochondria of photosynthetic tissue or from glucose via the glycolitic pathway in non-photosynthetic tissue

4. In addition to acetyl CoA, malonyl CoA is an essential substrate for fatty acid synthesis and is produced by the carboxylation of acetyl CoA, catalyzed by Acetyl-CoA carboxylase

Acetyl-CoA Carboxylase

The rate-controlling enzyme of FA synthesis • In Eukaryotes - 1 protein

(1) Single protein, 2 identical polypeptide chains

(2) Each chain Mwt = 230,000 (230 kDa) (3) Dimer inactive

(4) Activated by citrate which forms filamentous form of protein that can be seen in the electron microscope

Acetyl-CoA Carboxylasein Plants

1. It is located in the chloroplasts in leaf tissue and in plastids in seeds

2. Unlike the enzyme in animal tissue, this is not activated by citrate, instead small changes in stromal pH or Mg or K concentration can

markedly affect enzyme activity

3. The enzyme is also regulated by a heat stable factor found in leaves and is influenced by the ratio of ADP to ATP

4. High ATP levels activate the enzyme

Overall Reaction

CH3C~SCoA

O

CH3C-

O

CH2C~S-

O

ACP

HS-CoACO2

NOTE

Malonyl-CoA carbons become new COOH end

Acyl CarrierProtein

Malonyl-CoA + ACP

-OOC-CH2C~S-

O

ACP + HS-CoA

Initiation

Synthesis of long chain saturated fatty acids from acetyl-CoA and

malonyl-CoA

1. It take place on a complex enzyme called fatty acid synthetase

2. FA synthetase 3 groups:

a. Type I synthetase found in animals, yeast and some bacteria

b. Type II synthetases occur in most bacteria and plant tissue

c. Type III synthetase involved in the elongation of existing fatty acid

CH3C-

O

CH2C~S-

O

ACP

NADPH

CH3CH2CH2C~S-

O

ACP

CH3C- CH2C~S-

O

ACP

HO

H

CH3C- = C- C~S-

O

ACPH

H

-H2O

NADPH

-Carbon Elongation

D isomer

Reduction

Dehydration

Reduction

-Ketoacyl-ACP reductase

-Hydroxyacyl-ACP dehydrase

Enoyl-ACP reductase

-KS

CO2

-S-ACP

TERMINATION Ketoacyl ACPSynthase

Free to bindMalonyl-CoA

Transfer to KS

Split out CO2

Transfer to Malonyl-CoA

-CH2CH2CH2C~S-

O

ACP

When C16 stage is reached, instead of transferring to KS,the transfer is to H2O and the fatty acid is released

ACP

KS -SH

HSAcetyl-CoA

CoA-SH

-C-CH3

OS

KS S-C-CH3

OKS -SH

SH

CoA-SH

Malonyl-CoA

S -C-CH2-COO-

O

CO2C=O

CH2

C=O

CH3

S

O

CH3-CH -CH2-C-S

OH

OCH3-CH=CH-C-S

OCH3-CH2-CH2-C-S

S-C-CH2-CH2-CH3

O

KS

KS

NADP+

NADPH H+

NADPH H+

NADP+

H2O

Initiation or priming

Elongation

Fatty Acid SynthaseFatty Acid Synthase

-Ketoacyl-ACP reductase

-Ketoacyl-ACP reductase

-Hydroxyacyl-ACP dehydrase

-Hydroxyacyl-ACP dehydrase

Enoyl-ACP reductase

Enoyl-ACP reductase

-Keto-ACP synthase (condensing enzyme)

-Keto-ACP synthase (condensing enzyme)

Malonyl-CoA-ACP transacylase

Malonyl-CoA-ACP transacylase

Acetyl-CoA-ACP transacylase

Acetyl-CoA-ACP transacylase

-Ketoacyl-ACP synthase

-Ketoacyl-ACP synthase

TE

TE

Substrate Entry Reduction Thioesterasepalmitate release

Substrate EntryReductionThioesterasepalmitate release

ACP

ACP

HSSH

AT

AT

CH2

CH2

HSSH

CE

CE

MT

MTER

ERKR

KR DH

DH

Translocation

Translocation

Overall Reactions

Acetyl-CoA + 7 malonyl-CoA + 14NADPH + 14H+

Palmitate + 7CO2 + 14NADP+ + 8 HSCoA + 6H2O

7 Acetyl-CoA + 7CO2 + 7ATP 7 malonyl-CoA +7ADP + 7Pi + 7H+

8 Acetyl-CoA + 14NADPH + 7H+ + 7ATP Palmitate + 14NADP+ + 8 HSCoA + 6H2O + 7ADP +

7Pi

7H+

PROBLEM:

Fatty acid biosynthesis takes place in thecytosol. Acetyl-CoA is mainly in the

Mitochondria

How is acetyl-CoA made available to the cytosolicfatty acyl synthase?

SOLUTION:

Acetyl-CoA is delivered to cytosol from the mitochondria as CITRATE

acetyl-CoA

COO

COO

HO-C-COO

CH2

CH2

COO

COO

HO-C-COO

CH2

CH2

Citrate lyase

Acetyl-CoA

COO

COOCH2

C=O

COO

COOCH2

HO-C-H

NADH

OAA

L-malate

C=OCOO

CH3

NADP+

NADPH + H+

L-malate

mitochondria

CytosolPyruvate

Malic enzymeOAA

Acetyl-CoACO2

PyrCO2

Malatedehydrogenase

HS-CoA

Post-Synthesis Modifications

C16 satd fatty acid (Palmitate) is the productElongation

UnsaturationIncorporation into triacylglycerols

Incorporation into acylglycerol phosphates

C16 satd fatty acid (Palmitate) is the productElongation

UnsaturationIncorporation into triacylglycerols

Incorporation into acylglycerol phosphates

Elongation of Chain (two systems)

HS-CoA

R-CH2CH2CH2C~SCoAO

OOC-CH2C~SCoA

OCO2

Malonyl-CoA* (cytosol)

R-CH2CH2CH2CCH2C~SCoAO O

O R-CH2CH2CH2CH2CH2C~SCoA

NADPH NADH

1

- H2O2

NADPH3

Elongation systems arefound in smooth ER andmitochondria

CH3C~SCoA

OAcetyl-CoA(mitochondria)

DesaturationRules:

The fatty acid desaturation system is in the smooth membranes of the endoplasmic

reticulum

There are 4 fatty acyl desaturase enzymes in mammals designated 9 , 6, 5, and 4 fatty

acyl-CoA desaturase

Mammals cannot incorporate a double bondbeyond 9; plants can.

Mammals can synthesize long chain unsaturated fatty acids using desaturation and elongation

The Desaturase System requires O2 andresembles an electron transport system

Rule:

NADHCyt b5 reductase

Cyt b5O2

Saturated FA-CoA

(FAD)

NOTE:

1. System is in ER membrane

2. Both NADH and the fatty acid contribute electrons

3. Fatty acyl desaturase is considered a mixed function oxidase

2

2

3

1

Desaturase

Cyt b5

reductase

Cyt b5

C18-stearoly-CoA + O2 + 2H+

C18 9-oleyl-CoA + 2H2O

2 cyt b5 Fe2+ 2 cyt b5 Fe2+

2H+ + cyt b5 reductaseFAD

cyt b5 reductase FADH2

NADH + H+NAD+

Fatty acid desaturation systemFatty acid desaturation system

Desaturase

Palmitate

Stearate

Oleate

Linoleate

-Linolenate-Linolenate

Eicosatrienoate

Arachidonate

18:3(9,12,15)

18:2(9,12)

18:3(6,9,12)

16:0

18:0

Elongase

18:1(9)

Palmitoleate

16:1(9)Desaturase

Desaturase

Desaturase

Desaturase

Desaturase

Desaturase

Elongase

20:3(8,11,14)

20:4(5,8,11,14)

Other lipids

Permittedtransitionsin mammalsEssential

fatty acid

Plant Cell Wall They are not chemically homogeneous but composed of several

different materials They are not physically homogeneous but built up of distinct layers

The most important (90%) component of all plant cell walls of dicotyledonous are polysaccharides and about 10% is lignin,

protein, water and incrusting substance In monocot, the primary wall (the wall initially formed after the

growth of cell consists of 20-30% cellulose, 25% hemicellulose, 30% pectin, and 5-10% glycoprotein; when the cells reach its final size , the secondary wall consists mainly of cellulose, is added to

the primary wall Lignin which is a complex, highly ramified polymer of

phenylpropane residues

Polysaccharides

Micro-fibril polysaccharides1. Cellulose (plant cell wall)

2. Chitin (fungi cell wall)3. Β-1,4-mannans (green algae cell wall)

4. Β-1,3-xylans (green algae cell wall)

Matrix polysaccharides1. Hemicellulose

2. Pectins

Cellulose

The most abundant organic substance on earth, representing about half of the total organically bound carbon

An unbranched polymer consisting of D-glucose molecules which are connected to each other by glycosidic (β1→4) linkage

Each glucose unit is rotated by 180° from its neighbor, so that very long, straight chains can be formed with a chain length of

2000-8000 glucose residues About 150 cellulose chains are associated by inter-chain

hydrogen bonds to a crystalline lattice structure known as a microfibril

Plant cell wall micro-fibril

Cellulose micro-fibrils consisted of about 36 chains of cellulose, a polymer of b(14)glucose

These crystalline regions are impermeable to water

Micro-fibrils have unusual highly tensile strength, very resistant to chemical and biological degradation. They are very difficult to hydrolise

Plant cell wall micro-fibril

Many bacteria and fungi have cellulose-hydrolysing enzymes (cellulase)

These bacteria can be found in the digestive track of some animals enabling them to digest grass and straw

Hemicellulose

A group of polysassharide which were relatively easily extracted from various plant tissues

It can be extracted by alkaline solutionThe name is in corrected, it thought to be a precursor of

cellulose (half built cellulose) it consists of a variety of un-branched polysaccharides

which contain D-glucose, hexose and pentose3 subgroups: xylans, mannans and galactans

Pectin

A mixture of polymers from sugar acids such as D-galacturonic acids, which are connected by (α-

1→4) glycosidic linksSome of the carboxyl groups are esterified by

methyl groupsThe free carboxyl groups of adjacent chains are

linked by Ca and Mg

Lignin

An important constituent of the cell wall of xylemLignification of the cell wall occurs after the lying down

of the polysaccharides component of the walls and towards the end of growing period of the cells

The distribution of lignin in the wall is not uniformLignin strengthen the wall by forming a ramified network

throughout the matrix, thus anchoring the cellulose micro-fibril more firmly and protect the micro-fibrils of

the wall from chemical, physical and biological attack

Cellulose biosynthesis

1. It is formed at the outer surface of the plasmalemma

2. Cellulose is synthesized by terminal complexes or rosettes, consisting of cellulose synthase and associated enzymes.

Terminal complex (rosette)

Cellulose synthase

Cellulose synthase has not been isolated in its active form, but from the hydropathy plots

deduced from its amino acid sequence it was predicted to have eight trans-membrane

segments, connected by short loops on the outside, and several longer loops exposed to the

cytosol.

Initiation of new cellulose chain

synthesis

Glucose is transferred from UDP-glucose to a

membrane lipid (probably sitosterol) on the inner

face of the plasma membrane.

New cellulose chain synthesis (1)

Intracellular cellulose synthase adds several more glucose residues to the first one, in (b14) linkage, forming a short oligosacchairde chain attached to

the sitosterol (sitosterol dextrin).

New cellulose chain synthesis

Next, the whole sitosterol dextrin flips across to the outer face of the plasma membrane, where

most of the polysaccharide chain is removed by endo-1,4-

β-glucanase.

New cellulose chain synthesis

The dextrin primer (removed from

sitosterol by endo-1,4-β-glucanase) is now

(covalently) attached to another form of

cellulose synthase.

New cellulose chain synthesis

The UDP-glucose used for cellulose synthesis is

generated from sucrose produced from

photosynthesis, by the reaction catalyzed by

sucrose synthase (this enzyme is wrongly

named).

New cellulose chain synthesis (5)

• The glucose associated with UDP is a-linked.

• Its configuration will be converted by glycosyltransferases so the product (cellulose) is β-linked.

Matrix polysaccharides• They are synthesized in the cisternae of the golgi

bodies• Synthase enzymes catalyze the formation of pectin

and hemicellulose