This document summarizes three proteins - silk, elastin, and resilin. It discusses the introduction, production process, properties, chemical properties, and uses of silk. For elastin, it covers the introduction, properties, importance and its role in arteries. Resilin is introduced along with its properties and importance for enabling efficient jumping and wing movement in insects.

1. Silk
Elastin
Resilin
Arjun K Gopi
1St M.Sc BPS
Cbpst, kochi

2. Overview…
Silk :- Elastin :- Resilin :-
 Introduction
 Production Process
 Physical Properties
 Chemical Properties
 Uses
 Introduction
 Properties
 Importance
 Introduction
 Properties

3. Silk

4. Introduction :-
 Silk is a natural protein fibre, some forms of which can be woven into textiles. The protein fibre of silk
is composed mainly of fibroin and produced by certain insect larvae to form cocoons.[1] The best-
known type of silk is obtained from the cocoons of the larvae of the mulberrysilkworm Bombyx
mori reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-
like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus
producing different colours.
 The construction of silk is called sericulture.
 To produce 1 kg of silk, 104 kg of mulberry leaves must be eaten by 3000 silkworms. It takes about
5000 silkworms to make a pure silk.

5. Production process :-

6. Production process :-

7. Properties :-
 Silk has a smooth, soft texture that is not slippery, unlike many synthetic fibers.
 Silk is one of the strongest natural fibers but loses up to 20% of its strength when wet. It has a good
moisture regain of 11%. Its elasticity is moderate to poor: if elongated even a small amount, it remains
stretched.
 It will be weak if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty.
 Silk is a poor conductor of electricity and thus susceptible to static cling.
 Unwashed silk chiffon may shrink up to 8% due to a relaxation of the fiber macrostructure, so silk should
either be washed prior to garment construction, or dry cleaned. Dry cleaning may still shrink the chiffon
up to 4%. Occasionally, this shrinkage can be reversed by a gentle steaming with a press cloth.
Physical Properties

8. Chemical Properties
 Silk emitted by the silkworm consists of two main proteins, sericin and fibroin,
fibroin being the structural center of the silk, and serecin being the sticky
material surrounding it.
 The high proportion (50%) of glycine, which is a small amino acid, allows tight
packing and the fibers are strong and resistant to breaking. The tensile strength
is due to the many interceded hydrogen bonds, and when stretched the force
is applied to these numerous bonds and they do not break.
 Silk is resistant to most mineral acids, except for sulfuric acid, which dissolves it. It
is yellowed by perspiration. Chlorine bleach will also destroy silk fabrics

9. Uses :-
 used for clothing such as shirts, ties, blouses, formal dresses, high
fashion clothes, lining, lingerie, pajamas, robes, dress suits, sun dresses
and Eastern folk costumes.
 Silk's attractive lustre and drape makes it suitable for many furnishing
applications. It is used for upholstery, wall coverings, window
treatments (if blended with another fiber), rugs, bedding and wall
hangings.
 A special manufacturing process removes the outer
irritant sericin coating of the silk, which makes it suitable as non-
absorbable surgical sutures.
 New uses and manufacturing techniques have been found for silk for
making everything from disposable cups to drug delivery systems and
holograms

10. Elastin

11. Introduction :-
 Elastin is a protein in connective tissue that is elastic and allows many tissues in the
body to resume their shape after stretching or contracting. Elastin helps skin to return
to its original position when it is poked or pinched.
 Elastin is also an important load-bearing tissue in the bodies of vertebrates and used
in places where mechanical energy is required to be stored. In humans, elastin is
encoded by the ELN gene.
 Can be stretched to several times their normal length, but recoil back.
 Elastin is present in lungs, walls of large arteries, elastic ligaments.
 elastin is made of simple amino acids such as glycine, valine, alanine, and proline

12.  Insoluble protein polymer.
 Elastin is made by linking many soluble tropoelastin protein molecules, in a
reaction catalyzed by lysyl oxidase, to make a massive insoluble,
durable cross-linked array. The amino acid responsible for these cross-links is
lysine.
 defects in elastin include Marfan's Syndrome and emphysema caused
by α1-antitrypsin deficiency.
 The most common external signs associated with Marfan syndrome include
excessively long arms and legs, arm span being greater than height.
Properties :-

13. Elastin serves an important function in arteries as
a medium for pressure wave propagation to
help blood flow and is particularly abundant in
large elastic blood vessels such as the aorta.
Elastin is also very important in the lungs, elastic
ligaments, the skin, and the bladder, elastic
cartilage. It is present in all vertebrates above
the jawless fish.
Importance :-

14. Resilin

15. Introduction :-
 Resilin is an elastomeric protein found in many insects. It is part of what enables
insects of many species to jump or pivot their wings efficiently. It was first
discovered by Torkel Weis-Fogh in locust wing-hinges.
 Resilin is currently the most efficient elastic protein, Because of its high strain, low
stiffness, and high resilience.
 It does not have any regular structure but its randomly coiled chains are
crosslinked by di- and tri-tyrosine links.
 Resilin must last for the lifetime of adult insects and must therefore operate for
hundreds of millions of extensions and contractions; its elastic efficiency ensures
performance during the insect's lifetime. Resilin exhibits unusual elastomeric
behaviour only when swollen in polar solvents such as water.

16. Properties :-
 the superior mechanical properties of resilin, resilin-based proteins are
autofluorescent, display self-assembly properties, and undergo phase transitions in
response to temperature.
 These properties have potential application in designing biosensors or
environmentally responsive materials for use in tissue engineering or drug delivery.
 Furthermore, the capability of resilin-based biomaterials has been expanded by
designing proteins that include both resilin-based sequences and bioactive domains
such as cell-adhesion or matrix metalloproteinase sequences.
 These new materials maintain the superior mechanical and physical properties of
resilin and also have the added benefit of controlling cell response. Because the
mechanical and biological properties can be tuned through protein engineering,