BMP: EXP3 Electrophoretic Flashcards
What is an example of a macromolecule?
Protein
State the 4 levels of protein hierarchy
- Primary
- secondary
- Tertiary
- Quaternary
What AA belong too Aliphatic group?
- Glycine, Alanine, Valine, Leucine, Isoleucine (VAGIL)
What AA belong too hydroxyl or sulfur containing?
Cystesine, serine, threonine, methionine
(MCTS)
my(S) cat(s) takes(h) (H)
What AA belong to cyclic?
Proline
What AA belong to aromatic?
Tyrosine, tryptophan, phenylalanine
WHat AA are basic?
Hystidine, arginine, lysine
What AA are acidic and their amides
Aspartate, asparagine, glutamate, glutamine
What is the name of the heterotrimeric protein involved in cardiac and striated muscle contraction?
creatine kinase
What is the name of the family of isoenzymes that are considered to be agold standarded marker for myocardial infarctions?
Troponins (T,I,C)
What dies tetrameric mean in relation to proteins?
MAde of 4 subunits. Can be homotetrameric - composed of 4 of the same subunits or hetrotetrameric - composed of 4 different subunits
Describe the quaternary structure of the cardiac specific form of creatine kinase.
Hetrodimer: quaternary stucture has 2 side chains M and B
MM MB BB Mtype/ B type
As with all “wet” laboratory experiments it is important to consider the health and safety precautions which must be taken.
Provide a brief account of the minimal safety precautions that you would expect to be enforced during the handling of the carcinogen N-methylphenazoniummethosulphate solution.
- Adhere to COSSH
- Full protective equipment
- hadnle in fume cupboard
What are isoenzymes
Enzymes which catalyse the same reaction but have different stucture
What differences occur with isoenzymes - why is this?
Different properties due tod ifferent structures e.g. different primary structures
What are examples of isoenzyme families?
- Lactose dehydrogenase (LDH)
- Creatine kinases
- CYP450s
- Glutathione transferases
How can isoenyzmes be seperated?
Give a specific example and state when this can be used
Can be seperated by a variety of physiochemical proceedures e.g. if structural differences result in different chagres on the isoenzymes they can be serpeated by electrophoresis
What is electrophoresis?
It is when charged molecules are placed in a tank and migrate toward the pole of opposite charge.
The rate of migration is determined by the magnitude of charge and molecular weight of the molecule. This means molecules with slightly different charges will migrate at different rates and seperation will be effected.
The material to be seperated is to be seperated by an inert matrix such as cellulose acetate. The molecules of different charges migrate as discrete bands which may then be located by approproate staining method.
Visual appraisal allows an estimation of the relative proportions of various isoenzymes, whilst more acurate determination may be obtained by densitomeric analysis using a scanning densitometer
What is ah hard copy of seperation called?
Electopherogram
- What type of protein is LDH?
- What subunits is it composed off?
- What form of LDH is mainly found in the heart?
- What form of LDH is mainly found in the skeletal muscle and liver?
- tetrameric
- 2 35kDA subinits
- H
- M
What is the composition of:
- LDH1
- LDH2
- LDH3
- LDH4
- LDH5
- H4
- H3M1
- H2M2
- H1M3
- M4
What can knowing the isoenzyme concentration in the body/ different tissues be useful for?
If pathological changes in tissue/ organsoccur it may cause isownzymes to leak into blood effecting isoenzyme patterns in the blood. These patterns can be examined and allows for identification of damaged tossue
What type of reactions does LDH catlayse? what is this called?
Give an example
- oxidation reduction reactions - oxidoreductase enzyme
- Catalyses the oxidation of NADH to NAD+ and reduction of Pyruvate to Lactate:
- NAH+ + lactate <—> Pyruvate + NADred
This is a reversible reaction
What are the reaction steps invlilved in producing a coloured compound?
- NADH + Pyruvate <—> NAD+ + lactate
- NADH + MPSPoxd <—> NAD+ + MPSPred
- MPSPred + NBToxd <—> NBTred (blue) + MPSPoxd
What does MPSP and NBT stand for?
MPMS ‐ N‐Methylphenazoniummethosulphate
NBT ‐ Nitrobluetetrazolium
Why is there more variation in expression of isoemyznes in human than rat?
- In the lab rat they are kept under controlled condition e.g. light and DIET
- Humans lve diverse lifestyles and complex genetic profiles
Explain how such variations in protein structure within the human species can still lead to a functional, catalytically active enzyme.
- Changes at DNA level i.e polymorphic change the AA and hence protein structure
- this is okay if in non-critical area, if the AA is replaced with one of similar stucture, or if it is an advantage
Outline how certain isoenzymes may be used as a dianostic tool for diagnosing myocaridal infarction
Myocardial infarction and infectious hepatitis involve cell death of the affected tissue with the release of the cell contents into the blood.
MI: High levels of troponin (cTnI and cTnT) are released into the blood.
Creatine kinases (M:muslce, B:brain MB: cardiac) Reference range of BM:5% or less of the total CK
What classes of isoenzymes can impact drug metabolism
phase 1 - CYO450s
Phase 2 - glutathione S transferases
What type of hazzard are:
tissue homegenates -
developing reagent -
barbiton buffer -
sodium lactate -
