Techniques in protein analysis Flashcards
Includes the analysis, categorization of overall protein signatures of a genome
Proteomics
3 goals of Proteomics
Identify/compare proteins
Study the interactions of proteins
Predict cell behavior / develop drug target
This method is based on charge
Ion exchange chromatography (IEC)
This method is based on size
Size exclusion chromatography
Based on specific binding interaction
Affinity chromatography
Based on highly specific antibody-antigen interaction
ELISA
Western blot is done by ____, ____, and ____
Separation
Binding
Staining
SDS-PAGE separates proteins based on ______
Molecular weight
SDS-PAGE is also known as
Sodium dodecyl sulfate-polyacrylamide gel electrophoresis
It is a classical method based on molecular weight and charge
Two-dimensional gel electrophoresis (2-DE)
A modified 2-DE by fluorescent dye binding
Two-dimensional differential gel electrophoresis (2D-DIGE)
Why do smaller proteins migrate faster?
Less resistance to gel matrix
A detergent with a strong protein denaturing effect
Sodium dodecyl sulfate (SDS)
It forms a mesh-like matrix
Polyacrylamide
(True or False)
pH below their pI carry a net negative charge
(False)
Below pI = positive
Above pI = negative
pH at which the net charge of the protein is zero
Isoelectric point
pI of the protein is also called
Isoelectric point
Proteins are adsorbed into wells by Immobilization thru ____ & _____
Hydrophobic interaction
Covalent bonds
Various antigen-antibody combinations are used in this method
ELISA
The enzyme activity in ELISA is measured ______
Colorimetrically
4 types of ELISA
Direct
Indirect
Sandwich
Competitive
It is also known as the simplest ELISA
Direct
The color change in direct ELISA using a spectrophotometer
Red
How many antibodies are involved in direct ELISA
1
The most popular ELISA
Indirect
It uses an extra incubation step
Indirect ELISA
It is designed for detection of soluble antigens
Sandwich ELISA
(True or False)
In Indirect sandwich ELISA , the antigen is labelled with a second labelled antibody
False
labelled with unlabelled antibody
Used when antigens are contaminated with proteins
Sandwich ELISA
Useful when the target is a small molecule
Competitive ELISA
Rapid, accurate, cost-effective method of microbial identification
MALDI-TOF MS
The mass analyzer in MALDI-TOF MS
Time-of-flight (TOF)
Ion source in MALDI-TOF MS
MALDI
This laser is rarely used
Transversely Excited Atmospheric (TEA-CO2)
Nd:Yag stands for
Neodymium-doped yttrium aluminum garnet
Er:Yag stands for
Erbium-doped yttrium aluminum garnet
Matrix is used to ___ & ___ analyte molecules
dilute & isolate
Ions of different m/z (mass-to-charge) are dispersed in a time during their flight of known length
Time-of-flight
Consists of a series of ring electrodes with high voltage
Reflectron
(True or False)
Faster ions carrying more kinetic energy will travel a shorter path
False
Longer path
This analyzer is not suitable for analytes that are not stable enough to survive the electric field
Reflectron TOF analyzer
It leads to ionization and sublimation of both sample and matrix
MALDI
Basic and important for protein characterization
Intact Mass determination
It has widespread uses in proteomics to identify proteins from simple mixtures
Peptide Mass Fingerprinting (PMF)
It is generated by digesting proteins of interest with a sequence specific enzyme
Peptides
It is used to make wells or lanes to load samples
Comb
What do you use to clean glass plates before assembling the gel casting mold
Ethanol
This should be avoided when pouring acrylamide solution because it inhibits polymerazation
Contact w/ air (oxygen)
Allow acrylamide to polymerize for ___ minutes
20-30
It is highly concentrated when migrating thru a stacking gel prior to entering a separating gel
Proteins