Download File

Protein Structure
Danilo V. Rogayan Jr.
RMTU San Marcelino
•Outline
Categories of Proteins
•
Fibrous proteins
•
Globular proteins
I
Protein Denaturation & Renaturation
II
Functions of Proteins
III
Journal Related to the Topic
IV
V
Summary of Concepts
Categories of
Proteins
Categories of Proteins
•
•
Fibrous protein (found in skin, tendons, bones, and
muscles) does not dissolve in water (hydrophobic).
Globular protein (found in enzymes, some hormones,
and hemoglobin) can dissolve in water (hydrophilic).
•Globular and fibrous proteins
Globular Protein
Fibrous Protein
• Have complex tertiary and
sometimes quaternary
structures.
• Folded into spherical
(globular) shapes.
• Usually soluble as
hydrophobic side chains in
centre of structure.
• Roles in metabolic reactions.
• E.g. enzymes, haemoglobin in
blood.
• Little or no tertiary structure.
• Long parallel polypeptide
chains.
• Cross linkages at intervals
forming long fibres or sheets.
• Usually insoluble.
• Many have structural roles.
• E.g. keratin in hair and the
outer layer of skin, collagen (a
connective tissue).
•Globular and fibrous proteins
Globular Protein
Fibrous Protein
• Have complex tertiary and
sometimes quaternary
structures.
• Folded into spherical
(globular) shapes.
• Usually soluble as
hydrophobic side chains in
centre of structure.
• Roles in metabolic reactions.
• E.g. enzymes, haemoglobin in
blood.
• Little or no tertiary structure.
• Long parallel polypeptide
chains.
• Cross linkages at intervals
forming long fibres or sheets.
• Usually insoluble.
• Many have structural roles.
• E.g. keratin in hair and the
outer layer of skin, collagen (a
connective tissue).
•Fibrous Proteins
•
Keratins are a family
of fibrous structural
proteins
•Globular Proteins
•
Enzymes are proteins
that catalyze (i.e.
accelerate)
chemical reactions.
Denaturation
and
Renaturation
of Proteins
•What is Denaturation?
• Process
of partial or total alteration of
the native secondary, and/or tertiary,
and/or quaternary structures of proteins
or nucleic acids resulting in a loss
of bioactivity.
• It leads to temporary or permanent loss
of activity.
•When and How are Proteins
Denatured?
• At
Very High or Low pH.
• At
Very High Temperatures.
• By
Heavy Metal Ions.
• By
Small Polar Molecules.
A protein’s conformation can change in
response to the physical and chemical
conditions.
• Changes in pH, salt concentration,
temperature, or other factors can unravel or
denature a protein.
•
•
•
These forces disrupt the hydrogen bonds, ionic
bonds, and disulfide bridges that maintain the
protein’s shape.
Some proteins can return to their functional
shape after denaturation, but others cannot,
especially in the crowded environment of the
cell.
•
Usually denaturation is permanent
•Denaturation by Small Polar
Molecules
• Urea
( CO(NH2)2 ) in concentrated
solution will denature proteins.
• It disrupts the Hydrogen Bonds.
• This causes complete denaturation.
•Everyday Examples of
Denaturation
• When
milk curdles, the acidity increases.
• Thermal denaturation by cooking.
• Mechanical denaturation when whisking
an egg.
• Perming hair breaks then reforms the
disulphide bonds.
Function of
Proteins
Types of proteins according
to functions
Type
Examples
catalytic
enzymes: trypsin, nuclease, amylase
transport
hemoglobin, glucose transport protein
structural
collagen, elastin, keratin
A
defense
antibodies, fibrinogen
regulatory
insulin, thyroid stimulating hormone
contractile
actin, myosin
storage
ferritin
nutrient
seed proteins
Journal
Related to the
Topic
Summary of
the Concepts
Summary
•
•
•
There are two categories of proteins: the fibrous
protein and globular protein.
Process of partial or total alteration of the native
secondary, and/or tertiary, and/or quaternary
structures of proteins or nucleic acids resulting in a loss
of bioactivity.
Proteins have a multitude of functions required for life.
Quiz
•
Complete the table below.
Type
transport
structural
defense
regulatory
contractile
One Example
References
http://healthyeating.sfgate.com/6-primaryfunctions-proteins-5372.html
• http://examples.yourdictionary.com/exampl
es-of-protein.html
• https://en.wikipedia.org/wiki/Denaturation_(
biochemistry)
•
Marami pong salamat!