NonEnzymatic Proteins Flashcards
Structural Proteins
Highly repetitive secondary structures and a supersecondary structure (motif): generally fibrous in nature
Ex: Collagen (3 alpha helices to create strength and flexibility)
Actin
Structural Protein made of microfilaments
Tubulin
Structural Protein made of microtubules
Keratin
Structural Protein serving as a regulatory intermediate filament protein
Motor Proteins
One or more heads capable of force generation through a conformational change
- Responsible for muscle contraction and cellular movement
- Have catalytic activity (ATPases power movements)
Ex: Myosin, kinesins, dyneins
Binding Proteins
Proteins transport or isolate molecules by binding to them; have a stabilizing function
Cell Adhesion Molecules (CAMs)
Allow cells to bind to other cells or surfaces
Ex: Cadherins, integrins, selectins
Cadherins
Calcium dependent glycoproteins that hold similar cells together
Integrins
Two membrane spanning chains (alpha and beta). Permit binding and communicating with ECM, cell signaling and processes
Selectins
Allow cells to adhere to carbohydrates and are important in defense, inflammation and white blood cell migration (immune system)
Immunoglobulins
Antibodies - proteins produced by B cells that target antigens which may be a protein on the surface of a pathogen (invading organism) or a toxin
Antibody Methods
- Neutralize antigen
- Opsonization (mark pathogen for destruction)
- Agglutinating (clump together insoluble proteins to be digested by macrophages)
Biosignaling
Process by which cells receive and act on signals
Ion Channels
Proteins that create specific pathways for charged molecules through facilitated diffusion (passive)
Ungated Channels
Ion channels that are always open
Voltage Gated Channels
Ion channels that open within a range of membrane potentials (Depolarization creates a conformational change)
Ligand Gated Channels
Ion channels that open in the presence of specific binding substances (generally hormone or neurotransmitter)
Enzyme Linked Receptiors
Participate in cell signaling through extracellular ligand binding and initiation of secondary messenger cascades
G-Protein Coupled Receptors
Initiate secondary messenger systems:
- Ligand binds to alpha subunit activating GTP from the inactive GDP
- Alpha subunit dissociates from the Beta and Gamma Subunits
- Activated Alpha alters the activity of Adenylate Cyclase or Phospholipase C
- GTP is dephosphorylated to GDP and rebinds with the Beta and Gamma subunits
Types of G- Proteins
Gs - Stimulates cAMP (increases)
Gi - Inhibits cAMP (decreases)
Gq - Activates Phospholipase C
Homogenization
Crushing, grinding or blending of Cells / Tissues
Centrifugation
Isolate proteins from smaller molecules
Electrophoresis
Uses Polyacrylamide Gel to observe proteins migration in an electric field based on net charge and size
Native Page
Analyze proteins in native states and compare the molecular size or charge of proteins
*proteins can be recaptured from gel
SDS-Page
Denature protein; separates based on mass only
Isolectric Focusing
Separates proteins by isoelectric point (pI) in an electric field that protein stops moving when pH = pI
Anions (-) move toward the Anode (+)
Cations (+) move toward the Cathode (-)
Chromatography
Separates proteins based on their affinity for a stationary phase vs mobile phase (move farther)
Column Chromatography
Polar beads (stationary) and nonpolar solvent (mobile) The less polar the protein, the faster it will elute
Ion Exchange Chromatography
separates ions and polar molecules based on their affinity to the ion exchanger (charged column)
Anion-Exchange: desired molecule is negatively charged
Cation-Exchange: desired molecule is positively charged
Size Exclusion Chromatography
Porous beads capture small proteins so that large proteins elute first
Affinity Chromatography
Coat beads with a receptor that binds the protein or antibody of interest
Edman Degradation
Sequentially removes the N-terminus amino acid
UV Spectroscopy
Analyzes protein concentrations
Bradford Assay
Coomassie Brilliant Blue: Increased [ ] means increased blue color
