Biochemistry
Proteins
•Proteins= Proteios.
• Elements-SONCH
•diverse macromolecules
•form tens of thousands of proteins
•Proteins are polymers
•Amino Acid monomers
•Form 3-D structure,
Monomer
Polymer
•structure always
tells function
Protein
Examples of Functions
Classes of Proteins
1. Defensive proteins=antibodies
2. Transport proteins=hemoglobin,
carries oxygen
3. Signal-hormones-signal proteins
which send messages to regulate
metabolic processes, insulin
4. Structural- are found in the hair &
fibers that make up muscles, tendons
and ligaments.
5. Storage- the storage of molecules,
such as the protein in white eggovalbumin & in developing seeds.
6. Contractile- fibers that enable
muscles to move.
http://video.google.com/videosearch?sourceid=navclient&ie=UTF8&rlz=1T4TSHB_enUS237US238&q=muscle+contraction&um=1&sa=X&oi=video_result_group&resnum=4&ct=tit
le#
7. *Enzymes -are organic catalysts,
which control most chemical reactions
in the body
•20 Different
Amino Acids,
•Each one different
due to it’s Residue
(R) group,
•Some are essential
and some are
nonessential.
hydrophilic
•Some Hydrophilic
•Some hydrophobic
•Some are Neutral
hydrophobic
•Monopeptide or Amino Acid
R Group=Residue
•R group=residue group
•chemical group that makes
each Amino Acid different
from one another.
H
Alpha Carbon
Hydrogen Atom
Amino Acid
•Functional groups-participate in
chemical reactions and give the
R Group=Residue
molecule it’s characteristics.
•amino group
•carboxyl group
H
Alpha Carbon
Each Amino Acid
has an Alpha Carbon
Hydrogen Atom
Each Amino Acid has
an Hydrogen Atom
dipeptide
•Dipeptide-two Amino
Acids linked
A peptide bond is
formed with the C in the
Carboxyl group bonds
to the N in the Amino
group and a water
molecule is formed.
Peptide bond
Let’s Review
1. What are the subunits of Proteins?
2. What is formed when two amino acids are
linked together?
3.What specific type of bond is formed?
4. What causes this reaction to take place?
5.What is this process called?
Four levels of protein
• Primary Structure
1oIs the linkage
(peptide bond) of
Amino acids or
monopeptides
forming a
polypeptide,
2H2O
1o
•Secondary Structure 2ois the bonding between
hydrogen of
The amino group
and the oxygen of the
carboxyl group.
•Secondary Structure forms
•Alpha helix
•Pleated sheet.
Alpha helix
Pleated sheet
Tertiary Structure 3o,
Is the combination of the
Of the primary 1o
And secondary 2o,
Forming a 3-D
structure-= globular or
fibrous.
Primary-1o
Tertiary-3o
Secondary-2o
globular
fibrous
Tertiary Structure
Has many
interaction:
• R groups between
Amino Acids.
• hydrophilic,
•hydrophobic,
•Hydrogen bonds
•Ionic bonds
•Sulfur bridges
Denaturation & Renaturation of a Protein
Quaternary Structure 4o
Has two, three or four
tertiary
Structures forms a
golubular structure.
Examples are:
enzymes, muscle,
antibodies
and hemoglobin.
Hemoglobin the
oxygen carrying molecule
is globular and has four
subunits, 2 alpha and 2 beta
chains.
BioCD
Animations 5.4.1-5.4.5
Sickle Cell Anemia
• The Sickle Cell allele is found in people of
African, Mediterranean, & Asian decent where
malaria is common. Throughout evolution people
with this abnormal allele have a selective
advantage over others that don’t carry this allele.
Malaria
Malaria is carried by a protozoan
parasite-plasmodium, plasmodium
is found in mosquitoes and invades
red blood cells. When the parasite
enters the cell it causes the cell to
sickle in shape.
White cells then destroy these
damaged cells and not enough red
cells remain for the parasite to
reproduce. Malaria has kept this
allele frequency higher in Africa.
Origin of Sickle Cell
India
Zaire
Angola & Nigeria
Angola, Congo & Zaire
Angola, Zampia, Tanzania
& Zaire
Gambia, Congo,
Zaire & Angola
Nambia, Botswana, Mozanbique,
Kenya, Sudan, Libya,
Algeria & Mali
Sickle Cell Anemia
Is an inherited genetic
disease caused by a
mutation in the
Nucleotide sequence
of DNA causing the
protein molecule of
Hemoglobin to
change.
HbAHbA homozygous
HbSHbS homozygous
HbAHbS heterozygous
HbSHbA heterozygous
Overview of
Protein Synthesis
•Transcription
•Translation
Hemoglobin
CTTCAT
Mutation-Base Substitute
Normal
Thymine -1
Thymine -1
Net negative charge -2
Thymine -1
Net negative charge -1
Using Gel Electrophoresis to Diagnose
Sickle Cell Anemia (Hemoglobin)
Normal Sickle Carrier
Cell
P1
P2
CT T
CA T
+
Controls
Known's
Unknown's
The change takes place in the sequence of the beta
chain of Amino Acids, Glutamic acid (polar) is
replaced with Valine (nonpolar), this causes a
reduction in the pH causing blood to become acidic
causing the abnormal hemoglobin to link and
crystallize, cells deform and become sickle or
crescent in shape.
This result causes
Pleiotrophy
Pleiotrophy is
one gene
that causes
many
different
characteristics
.
Future Breakthrough for Sickle Cell
•Scientist are hoping
to use a new
medication that will
dilate the blood
vessels in patients.
Bone marrow
transplants