.pdfbio polymers and elastin Bio Medical

Biopolymers are natural polymers produced by living organisms. They play essential roles in various biological processes and structures. Common examples include proteins, nucleic acids, polysaccharides, and lipids. Biopolymers are biodegradable and often have unique properties that make them suitable for a range of applications, including pharmaceuticals, food packaging, and medical devices.

Elastin is a specific type of protein biopolymer found in connective tissues, such as skin, lungs, and blood vessels. It provides elasticity and resilience, allowing tissues to stretch and return to their original shape. Elastin is composed of amino acids, primarily glycine, valine, and proline, and is critical for maintaining the structural integrity and flexibility of tissues throughout the body. Its ability to withstand deformation and provide mechanical support makes it vital in organs that undergo significant stretching and recoil.

1. KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India

2. BIOPOLYMERS

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O Biopolymers are polymers formed in nature during the growth cycles
of all organisms, hence, they are referred as natural or biological
polymers.

O Their synthesis always involves enzyme catalyzed chain growth
polymerization reactions of activated monomers, which are

generally formed within the cells by complex metabolic processes.

O The most prevalent structural biopolymers are the polysaccharide

cellulose in higher plants and protein collagen in animals.

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India

3. == E E

Collagen
Elastin
Cellulose
Chitin

als
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BIOPOLYMERS

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India

4. ELASTIN alg
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Elastin is a structural protein found in a relatively large
amount in elastic yellow connective tissue that occur in
ligaments, lung, aortic wall and skin.

It is a protein with rubber like elastic properties whose
fibers can stretch to several times their normal length.
Elastin, like collagens has a distinctive amino acid
composition.

It consists predominantly of small, nonpolar residues.

It has one third glycine, over one-third Alanine, Valine
and rich in proline.

It contains little hydroxyproline, no hydroxylysine and
few polar residues.

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India
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5. COMPOSITION OF ELASTIN alla

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Amino acids mol /100 amino acids

Gly 324

Hyp 26

Asp, Glu 2.1

His, Lys, Arg 13

Nonpolar amino acids Pro, Ala, Val, Met, Leu, Ileu, Phe, Tyr 59.5

Cys 0.4

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India

6. STRUCTURE OF ELASTIN

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® The elastin protein is composed largely of two types of
short segments that alternate along the polypeptide
chain:

Y hydrophobic segments, which are responsible for the
elastic properties of the molecule; and

Y alanine- and lysine-rich a-helical segments, which form
cross-links between adjacent molecules

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India

7. ELASTIN

S
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1 23456 78 9 ums 16 17 18 1920212223 24 2526 2728 293031323336

| 3'-Untranslated region [l 5'-Untranslated region D Signal peptide

Hydrophobic exon | Hydrophilic cross-linking exon I Hydrophilic C-terminus

FIGURE 1 | Human tropoelastin domain structure. Tropoelastin contains alternating hydrophobic (write rectangle) and hydrophilic cross-linking domains (black
rectangle), and the width of the rectangles corresponds to the length of the domains. The nu above the domains represents the sequence of exons that encode
them. Among exons, exon 36 encodes a hydrophilic C-terminus (red rectangle) in addition to a 3'-untranslated region (blue rectangle).

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India

8. ELASTIN ala

a <PRIET
Elastin pit
Major protein component Bun
of elastic tissues such as _— —
arteries, lungs, skin

Highly cross-linked 5 v

,insoluble OS

sreerca | | PEAY

Rubber like consistency
single elastin molecule

cross-link —_ mu
Amorphous, no regular 2ry

structure ,but only random coils

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India

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9. SYNTHESIS OF ELASTIN

Microfibrils nn
EE

Endoplasmic
reticulum

nu Tropoelastin WA Crosslinked elastin © LOX ==EBP

10. ELASTIN alg
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Unlike collagen fibers, elastin is devoid of regular
secondary structure.

The covalent cross-links in elastin are formed by
allylsine aldol and lysinonorleucine, desmosine and
isodesmosine.

Desmosine and isodesmosine are unique to elastin and
are responsible for its yellow color.

They result from condensation of three allysine and one
lysine side chains.

Elastin fibers are also composed of microfibrillar
proteins that form the outer core of elastic fibers.

according to the location within the skin.
KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India
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11. ELASTIN alls
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0 Elastin is stable to relatively high temperatures and”
chemical reagents due to low content of amino acids
with polar side chains.

O The enzyme elastase, hydrolyses elastin at peptide
bonds after small hydrophobic residues, particularly
alanine.

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India

12. ELASTIN

ELASTIN pl

a PROTEIN that gives skin ELASTICITY,
allowing it to STRETCH and bounce back

Youthful Skin Older Skin

PLENTY of “JustAboutSkin.com MUCH LESS
collagen & elastin in aged skin

KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, India
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