MCAT Biochemistry Ch. 3 Nonenzymatic Protein Function & Protein Analysis

Make up the cytoskeleton, anchoring proteins, & extracellular matrix. Include collagen, elastin, keratin, & tubulin.

Have 1 or more heads that can generate force through a conformational change. They have catalytic activity, acting as ATPases to generate movement like muscle contraction, vesicle movement, & cell motility. Include myosin, kinesin, & dynein.

Bind a specific substrate, to either sequester it in the body or hold its concentration at a steady state.

Allow cells to bind to other cells or surfaces. Include cahedrins (hold similar cells together), integrins (help cells stick to proteins), & selectins (help sells to stick to carbohydrates)

Used by immune system to target a specific antigen. Contain constant & variable (region responsible for antigen binding) regions. Have 2 heavy & 2 light chains held together by disulfide linkages & noncovalent interactions

Regulate ion flow into & out of cell. 3 types: ungated, voltage-gated, & ligand-gated

Always open. *The channels responsible for keeping a cell at its resting membrane potential are ungated channels

Open w/in a range of membrane potentials

Open in the presence of a specific binding substance, usually a hormone or neurotransmitter

Participate in cell signaling through extracellular ligand binding & initiation of second messenger cascades

Have a membrane-bound protein associated w/ a trimeric G protein. Initiate second messenger systems (pg. 99 for process)

Uses gel matrix to observe the migration of proteins in response to an electric field. Includes Native PAGE, SDS-PAGE, & Isoelectric Focusing

Maintains proteins shape, but results are difficult to compare because the mass to charge ratio differs for each protein

Denatures the proteins & masks their native charge so that comparison of size is more accurate, but functional protein is destroyed in process

Separates proteins by their pI. The proteins migrate toward an electrode until they reach a region of gel where pH = pI of the protein. The anode is positively charged and acidic pH & the cathode is negatively charged & basic pH