Ch3 BC: Nonenzymatic Protein Function & protein Analysis

Proteins

Molecules that support cellular functions and structure.

Enzymes

Proteins that catalyze biochemical reactions.

Structural Proteins

Proteins providing support and shape to cells.

Cytoskeleton

Three-dimensional web providing intracellular support.

Extracellular Matrix

Network of proteins supporting body tissues.

Collagen

Trihelical fiber providing strength in connective tissue.

Elastin

Protein allowing tissues to stretch and recoil.

Keratins

Intermediate filament proteins in epithelial cells.

Actin

Most abundant protein forming microfilaments.

Tubulin

Protein forming microtubules for cellular structure.

Motor Proteins

Proteins facilitating movement along filaments.

Myosin

Primary motor protein interacting with actin.

Kinesins

Motor proteins transporting vesicles toward microtubule plus end.

Dyneins

Motor proteins transporting vesicles toward microtubule minus end.

Binding Proteins

Proteins that transport or sequester molecules.

Oxyhemoglobin Dissociation Curve

Graph showing hemoglobin's affinity for oxygen.

Cell Adhesion Molecules (CAMs)

Proteins aiding cell attachment to matrices.

Cadherins

Glycoproteins mediating calcium-dependent cell adhesion.

Integrins

Proteins binding to extracellular matrix for signaling.

Selectins

Proteins binding to carbohydrates on cell surfaces.

Immunoglobulins

Antibodies produced by B-cells for immune response.

Antibodies

Proteins neutralizing foreign invaders in the body.

Cellular Transport

Movement of substances within and outside cells.

Microfilaments

Filaments composed mainly of actin proteins.

Microtubules

Cylindrical structures made of tubulin proteins.

Sarcomere

Basic unit of muscle contraction containing actin and myosin.

ATPases

Enzymes that hydrolyze ATP for energy.

Retrograde Transport

Transport of materials back to the cell body.

Epithelial Cells

Cells forming protective layers in organs.

Tendons

Connective tissues attaching muscles to bones.

Ligaments

Connective tissues connecting bones to other bones.

Basement Membranes

Thin layers supporting epithelial cells.

Antigen-binding region

Specific site on antibody for antigen attachment.

Constant region

Part of antibody involved in immune cell recruitment.

Antigens

Targets that antibodies bind to in immune response.

Neutralization

Inactivating pathogen or toxin by antibodies.

Opsonization

Marking pathogens for destruction by immune cells.

Agglutination

Clumping of antigens and antibodies into complexes.

Biosignaling

Cellular process of receiving and acting on signals.

Ion channels

Proteins creating pathways for charged molecules.

Facilitated diffusion

Passive transport through membrane protein channels.

Ungated channels

Ion channels without regulation or gates.

Voltage-gated channels

Channels opening in response to membrane potential changes.

Ligand-gated channels

Channels opening upon ligand binding.

Michaelis-Menten equation

Describes enzyme kinetics and transporters' activity.

Enzyme-linked receptors

Receptors with catalytic activity upon ligand binding.

Receptor tyrosine kinases

Enzyme-linked receptors that dimerize upon ligand binding.

G protein-coupled receptors

Integral proteins involved in signal transduction.

Heterotrimeric G protein

G protein with three subunits: alpha, beta, gamma.

cAMP

Second messenger increased by G protein stimulation.

Phospholipase C

Enzyme activated by G protein to cleave phospholipids.

PIP2

Phospholipid cleaved into DAG and IP3.

DAG

Second messenger involved in signaling pathways.

IP3

Inositol trisphosphate that opens calcium channels.

Protein purification

Isolating specific proteins from complex mixtures.

Cell lysis

Breaking down cells to release proteins.

Centrifugation

Technique to separate proteins from smaller molecules.

Homogenization

Mixing tissue into a uniform solution for extraction.

Electrophoresis

Separation method using electric field for proteins.

Migration Velocity (v)

Speed of molecule movement in electric field.

Electric Field Strength (E)

Force applied to charged particles in electrophoresis.

Net Charge (z)

Overall charge of a molecule affecting migration.

Frictional Coefficient (f)

Resistance affecting molecule movement in gel.

Polyacrylamide Gel

Standard medium for protein electrophoresis.

Native PAGE

Analyzes proteins in their natural states.

SDS-PAGE

Separates proteins based on molecular mass.

Sodium Dodecyl Sulfate (SDS)

Detergent that denatures proteins and adds charge.

Isoelectric Point (pI)

pH where protein has no net charge.

Zwitterion

Electrically neutral form of amino acids.

Isoelectric Focusing

Separation based on proteins' isoelectric points.

pH Gradient

Varied pH across gel in isoelectric focusing.

Chromatography

Technique to separate compounds by physical properties.

Stationary Phase

Solid medium where sample is applied in chromatography.

Mobile Phase

Liquid that moves through stationary phase in chromatography.

Retention Time

Time a compound spends in stationary phase.

Partitioning

Separation of components within stationary phase.

Charge Migration

Movement of charged molecules towards oppositely charged electrodes.

Functional Native Protein

Protein retained in native state post-electrophoresis.

Mass-to-Charge Ratio

Comparison affecting protein migration in PAGE.

Basic Amino Acids

Amino acids with basic side chains affecting pI.

Acidic Gel

Gel side with lower pH in isoelectric focusing.

Basic Gel

Gel side with higher pH in isoelectric focusing.

Electrophoretic Mobility

Rate of migration of charged molecules in gel.

Protein Bands

Visible separation of proteins after staining gel.

Size-Exclusion Chromatography

Technique separating proteins based on size.

Analytical Techniques

Methods used to analyze proteins and compounds.

Column Chromatography

Technique using gravity to separate compounds in a column.

Silica Beads

Common adsorbent used in column chromatography.

Elution

Process of washing out compounds from column.

Polar Compounds

Compounds that interact strongly with polar stationary phases.

Ion-Exchange Chromatography

Technique separating proteins based on charge.

Salt Gradient

Increasing salt concentration used to elute bound proteins.

Affinity Chromatography

Technique using specific binding to isolate proteins.

Coomassie Brilliant Blue

Dye used in Bradford protein assay for quantification.

Protein Hydrolysis

Process to break down proteins into amino acids.

Edman Degradation

Method for sequencing proteins up to 70 amino acids.

Chymotrypsin

Enzyme used for specific protein cleavage.

Protein Activity

Measured by monitoring reactions with substrates.

Spectroscopy

Technique for determining protein concentration.

Bradford Protein Assay

Assay using Coomassie dye to quantify proteins.