Winter exam questions Flashcards
What is the best expression host to use and why?
Mammalian cells are preferable as they have a higher PTM modification compared to bacteria. Although they are slow and expensive
Talk about upstream and downstream
Upstream: Cells are modified to express the gene of interest. They’re grown in large quantities. They manufacture the protein of interest and secrete it into the media
Downstream: 1: media is filtered to reduce bulk volume and retain product. 2: Purification steps. 3: Bioanalytical analysis. 4:Antiviral. 5: Sterile fill and vialing
Which form of amino acids is found in proteins?
L-form of zwitterionic molecules
Define enzymes
Highly selective catalysts that convert substrates into products. In the biopharma industry, Enzymes
accelerates the reaction by lowering the activation energy of a reaction
a good example is urease
They don’t take part in the reaction
Define cellular respiration
The generation of ATP in all living things. Lipid oxidation is where the most ATP is produced. Red cells do not respirate
Talk about cox 1 and cox 2
Asprin inhibits by binding to enzyme Cox 2. This prevents production of prostiglandins. Cox 2 normally binds to archeadonic acid and converts to prostiglandins which cause an inflammatory immune response (pain) . An off target side effect is that cox 1 is inhibited which produces cytoprotective prostoglandins to prevent gastric mucosa. This results in ulcers and indegestion
What is the active site?
The part of the protein in which the substrate binds to. its the region in the enzyme that comprises of amino acid residues. 5-8 amino acids makes up the active site. The protein needs a 3D shape so the Amino acid can bind to the substrate
Characteristics:
Amino acids might be separated
The protein must be properly folded for the amino acid to bind
Substrate binds via hydrogen bonds
Enzymes can have more than one substrate
What are the 4 types of specificity in enzymes and describe what they are
Bond specificity: When an enzyme only reacts with a specific chemical bond
Group specificity: When an enzyme will only react to substrates with similar functional groups
Optical/stereo specificity: When the enzyme is not specific to substrate but also optical configuration
Dual specificity: Can convert two substrates at once, may act on one substrate by two different reaction types
What is an Apoenzyme?
Apoenzyme is an enzymatically inactive protein part of an enzyme, which requires a cofactor for its activity
Differences between cofactors and co-enzymes
Cofactors are non-proteins which assist enzymes in performing
catalytic actions.
Cofactors are metals i.e. cations
Co-enzymes are more organic, i.e. vitamins e.g. ATP
Some enzymes require 1 or both
Give three examples of cofactors and the enzyme/protein they code for
Zinc = Carbonic anhydrase
Zinc = Alcohol dehydrogenase
Potassium and magnesium = Pyruvate phosphokinase
Name a cofactor that is permanently attached
Haem in Haemoglobin
What are the 6 classes of enzymes based on reaction catalysed and what is the reaction carried out
Oxidoreductase: Transfer of reactions, i.e. alcohol dehydrogenase
Transferases: Transfer of C,N or P groups, i.e. Hexokinase
Hydrolases: Bonds cleavage by adding water i.e. Trypsin
Lyases: Cleavage of the same elements to make a double bond i.e. Pyruvate decarboxylase
Isomerases: Forms optical or geometric isomers i.e. Maleate isomerase
Ligases: Hydrolysis of high energy phosphates to form new bonds i.e. pyruvate carboxylase
What is the most common structural characterisation of enzymes involved in glycolysis
Oligomeric enzymes
What does “ “ refer to in EC classification
A:
B:
C:
D:
A: type of reaction
B: Subclass indicating type of substrate
C: Sub-sub classes, precise bond/reaction catalysed
D:Individual reaction
What is the differences between continuous assay and discontinuous assays
Continuous assay are measured in real time with continuous monitoring this means that the reaction proceeds without stopping which results in gathering immediate data and detailed kinetic information.
Discontinuous assays collects data from samples taken at specific intervals and the reaction is stopped at set points. This results in limited kinetic data
What is a reversible inhibitor?
A molecule that binds to an enzyme and temporarily blocks it which alters the 3D shape of the enzyme. It doesn’t permanently inactivate the enzyme and can be removed when the condition changes. There are 3 types, competitive, non competitive and uncompetitive
What is meant by Q10?
Its the factor in which the rate of the enzyme increases with a 10 degree rise
How are antibodies used in industry?
Therapies: Humeric
Biomarkers for disease: ELIZAS = Tyrosine
Research: GFP
What is the differences between monoclonal and polyclonal **
Monoclonal: Identical protein molecules
Bind to only one epitope
Specific binding
Easier to manufacture
Production takes up to a year
Used directly in therapies i.e. IV (Due to IV’s going into the blood stream, it has to be done by a med professional which is inconvenient)
Polyclonal: A mixture of protein molecules (antibody)
They vary in the FAB region
They’re sensitive which is an advantage
Used in diagnostic assays i.e. ELISAS
They have some research applications
What are the effector functions of antibodies?
They block ligand- receptor interactions (auto immune)
Cause cell lysis through activating complement dependent cytotoxicity (Fights cancer)
interacts with FC receptors on effector cells to engage antibody cell cytotoxicity (Cancer)
Signal for ingestion of a pathogen by a phagocyte (Cancer)
Why is IgG used in commercial drug manufacturing?
Effector mechanism
Bioavailability ( stable in blood)
MAB purification (Affinity chromatography)
IgG1 is the major Ig in serum with fluid carrying vessels
IgG is the only class of Ig that crosses the placenta.
Binds macrophages and monocytes increases efficiency
Down stream purification is possible even in large volumes
What are the 5 immunoglobin classes and functions?***
IgG: Monomer, capable of carrying out all effector functions from the serum and can travel around the body
IgM: Pentamer, the first Ig to be made by the fetus, is a good complement fixing Ig
IgA: Monomer, made in the plasma, found in tears and saliva doesn’t fix complement
IgD: Only exists as a monomer, found in low levels of serum
IgE: Monomer, least common serum as it binds to Fc receptors, involved in allergic reactions
What are some advantages to immunoassays?
They are are highly sensitive, it detects low quantities of Ag
Highly specific, relies on specificity of AB component
High thorough put
Cost efficient