Zusammenfassung der Ressource
Basic Genetics
- Protein sequence from amino to carboxyl end N-C
- Primary Structure:
no interactions or stabilising bonds
- Secondary Structure:
H bonding between
carbonyl oxygen and
amide hydrogen
- Tertiary Structure:
myoglobin and
Haemoglobin
- Quaternary Structure:
4 subunits interacting.
Has 4y structure
- PROTEIN PURIFICATION - BY SIZE
- ULTRAFILTRATION
- Small molecules forced
through membrane by
pressure or
centrifugation
- DIALYSIS
- Semi-permeable
membrane, small
molecules pass out
- GEL FILTRATION
- Large molecules out
first and large
amounts of protein
can be separated
- PROTEIN PURIFICATION - BY CHARGE
- net +ve charge
binds to -ve
molecules
- net -ve charge
binds to +ve
molecules
- Separate in a column
containing beads
- ROLES OF BLOOD
- Transports nutrients to tissues, including O2
- Removes waste products
- Protects against infection
- Repair of tissue damage
- BLOOD CELLS
- Erythrocytes (RBCs)
Transports oxygen
- Leukocytes (WBCs)
Lymphocytes, monocytes
and granulocytes. Protects
against infection
- Platelets (thrombocytes)
Cell fragments and blood
clotting
- ALBUMIN
- 3 Domains
- Free Cys
- Alpha helix, no beta sheet
- No glycolysation
- Most abundant
- Important in solubilisation,
transport and removal of
hydrophobic molecules in
hydrophilic environment of plasma
- ALBUMIN IN OSMOTIC REGULATION
- High concentration in plasma
- Prevents tissue taking up excess water
- Osmolarity of plasma decreases (less protein)
- Water enters tissues
- OEDEMA - swelling
- BLOOD CLOTTING CASCADE
- As a result of damage to blood vessels
- Prevents excess blood loss
- 2 STEP PROCESS
- 1) Platelet Agreggation
- Platelets adhere to vessel wall and
aggregate. Forms 1y plug and needs to
be stabilised
- 2) Activation of coagulation factors
- Plug stabilised by X-linking of FIBRIN
and forms 2y plug
- Cascade is tightly regulated and
zymogen activated
- Catalytic proteases activate next
factor
- Controlled by inactivation of proteases by inhibitors
- Large amplification of response to
damage = rapid response
- HAEMOGLOBIN
- 4 sub units
- much alpha helix
- 4 haem groups
- Binds oxygen in lungs as CO2 released,
pH is raised and allosteric action
results in high affinity
- Carries oxygen to tissues where pH is
lower and HCCO2 inhibits binding by
allosteric action
- Oxygen transferred to
myoglobin, which now has
higher affinity
- ACUTE PHASE PROTEINS
- C - Reactive Protein (CRP)
- 5 units form penraxin ring
- Binds to phosphoryl choline and
nucleic acids
- Activates complement to lyse bacteria
- Scavenger for nucleic acid
from cell necrosis
- APP in human, dog and pig. Not in cat, horse, cow.
- Serum Amyloid A (SAA)
- Many hydrophobic amino acids
- Involved with cholesterol transport
- Antibacterial activity
- 4 isoforms in most species.
1+2 acute phase stimulated, 3
is produced by non-hepatic
tissue in the acute phase. SAA
4 is not an APP
- stimulates mucin production in intestine
- Present in colostrum and milk from cows with mastitis
- Class of proteins whose plasma
concentrations increase or
decrease in response to
inflammation
- Haptoglobin
- 2 alpha and 2 beta sub units
- In ruminants forms high
mol weight polymers
- In ruminants, a major APP
- In dog, cat, horse and pig, a moderate APP
- In dog, Hp is stimulated by
cortisol as well as in acute
phase response
- Binds strongly to free
haemoglobin
- Haemoglobin binding is the basis of a rapid assay
- Anti-oxidant activity
- Alpha 1 Acid Glycoprotein
- Highly glycosylated + soluble
- >40% is attached to carbohydrate
- Binds to drugs + endogenous ligands
- Can alter the free concentration of drugs
- Shows immunomodulatory activity
- Reduces bacterial spread by
reducing vascular permeability
- TRANSFERRIN
- Transports Fe as ferric ion
- Both alpha helices and beta sheets
- Forms 2 different lobes, N
and C terminus
- Domains are held together by a short peptide
with a deep hydrophobic site
- FE 3+ BINDING
- The amino acids binding
ferric iron ion are the same
for both lobes
- The binding of iron also
needs an anion which is
usually carbonate (CO3 2-)
- Binding stabilised
by: Tyr 192, tyr 92, His
253 and ASP 301