Biochemistry: Proteins Flashcards
What are…
The 4 Main Bio-molecules in the Human Body
- Proteins (17.0%)
- Lipids (13.8%)
- Carbohydrates (1.5%)
- Nucleic Acids
Define
Proteins
- the most abundant and functionally diverse molecule in living systems
- a macromolecule consisting of alpha-amino acids connected by peptide bonds
- organic nitrogenous compound that are high in molecular weight
- polymers of amino acids
Percents
What are the 5 major elements of protein?
- Carbon (50-55%)
- Oxygen (19-24%)
- Nitrogen (13-19%)
- Hydrogen (6-7.3%)
- Sulfur (0-4%)
8 Functions and their Type of Protein are:
- Catalytic Function [enzymes]
- Regulatory Function [hormones]
- Gene Regulatory Function [genetic proteins]
- Protection Function [defensive proteins]
- Transportation Function [transporters]
- Storage Function (storage proteins)
- Contractile Function (contractile proteins)
- Structural Function (structural proteins)
Amino Acid Formula:
R-CH(NH2)-COOH
The major building block of protein is
alpha amino acids
Amino acids in living organisms can be found as both
state
- free form
- in the form of peptides and protein
What are chaperones?
They are a specialized group of proteins required for proper folding of proteins.
Where do peptide bonds happen in 2ry and 3ry structures?
and between what
The folding of 2ry and 3ry structures have a peptide bond between -CO and -NH.
Disulfide bridge in insulin:
3:
- 1 intrachain in the A chain
- 2 interchain between the A and B chains
Are there disulfide bonds in the primary structure of a protein?
NO, they are in the tertiary structure. (3D)
What does it mean that a peptide bond has coplanarity?
It means that there is partial sharing of two pairs of electrons between the amide nitrogen and carboxyl oxygen
Where is free rotation prevented?
Between the carbonyl carbon and the nitrogen of the peptide bond
What purposes does the disulfide bridge serve in insulin?
5
- Preserves structure
- Stabilizes 3ry and 4ry structures
- Functional conformation needed for insulin’s biological activity
- Enables insulin to interact correctly with insulin receptors
- Role in regulating blood glucose levels
How does the primary structure get sequenced?
genes
- unique a.a sequence determined by genes
- mutation can lead to a change in these a.a sequences and cause disease.
What is the healthy sequencing of hemoglobin A (HbA)?
Glutamic acid in position 6
In abnormal hemoglobin S (Hb S), what is in position 6?
Valine
remember “surveilance”
In abnormal haemoglobin C (Hb C) what is in position 6?
Lysine
What is Hb S and what can happen due to it?
Sickle cell disease, where Hb S is a variant of the protein that causes sickle cell anemia.
- at low oxygen levels: altered hemoglobin molecules bond together and distort the shape of RBCs, creating abnormal sickle-shaped cells.
Ketogenic a.as are:
- Leucine
- Lysine
LK
Glucogenic a.as:
ALL a.as except (ile, tyr, trp, phe, leu, lys)
mixed ketogenic and glucogenic a.as:
- isoleucine i
- tyrosine y
- tryptophan w
- phenylalanine f
IFWY (i f w you) mixed
semi-essentials
which a.as are needed for growing children but not adults?
His h & Arg r
semi-essential
which a.as are needed post-trauma/surgery?
His h & Gln Q
Essential a.as:
8
FHIKLMTVW
semi-essential a.as:
HRQ
non-essential a.as:
ACDEGNPSQY
akdynepsiky
If pH is greater than pl…
the amino acid is negatively charged.
if the pH is less than pl…
then it is positively charged
which amino acids have a taste?
- glycine & alanine (sweet)
- arginine (bitter)
T/F: a.as have very high melting points
True! (200-300 celsius)
- because of hydrogen and ionic bonds
at melting point, they…
are in their crystalline/ zwitterionic structure
Colour of a.as:
Colourless, they are crystalline
T/F: solubility in water increases as a.as is considered polar/ charged.
True. Polar a.as can form hydrogen bonds so they are more soluble in water.
Where do non-polar a.as exhibit high solubility?
non-polar solvents
examples:
1. benzene
2. chloroform
3. ether
Are a.as soluble at pl?
NO, AAs are insoluble at isoelectric point because of the net neutral charge.
What can increase solubility of AAs?
higher temp
example:
tyrosine is soluble in hot water
