Proteomics

Protein

Essential molecules responsible for chemical reactions, structure, gene control, hormone regulation, immune defense, transport, and muscle contraction.

Digestive Enzymes

Amylase, Lipase, Pepsin - Break down food for absorption.

Transport Protein

Hemoglobin - Carries substances in blood.

Structural Proteins

Actin, Tubulin, Keratin - Build body structures.

Hormone Signaling Proteins

Insulin, Glucagon - Regulate body functions.

Defense Proteins

Antibodies - Protect against infections.

Contractile Proteins

Myosin - Enable muscle movement.

Storage Proteins

Egg white, Legume proteins - Store nutrients for growth.

Protein Structure

Made of amino acids linked by peptide bonds; sequence determines function.

Peptide/Oligopeptide

Short chain of amino acids.

Polypeptide

Chain with more than 80 amino acids.

Multisubunit Protein

Multiple polypeptides linked together.

Amino Acid Properties

Nonpolar (hydrophobic), Polar (hydrophilic), Acidic (negative charge), Basic (positive charge).

Special Amino Acids

Glycine (smallest), Cysteine (forms disulfide bonds), Tyrosine (hydrophobic yet can form hydrogen bonds).

Primary Protein Structure

Specific sequence of amino acids.

Secondary Protein Structure

Local folding into alpha helices or beta sheets.

Tertiary Protein Structure

Overall 3D shape of the protein.

Quaternary Protein Structure

Multiple polypeptide chains forming a complex.

Alpha Helix

Right-handed spiral stabilized by hydrogen bonds.

Beta-Pleated Sheet

Extended, sheet-like structure stabilized by hydrogen bonds.

Protein Folding

Polar side chains on the outside, hydrophobic core.

Parallel Beta Sheet

Polypeptide chains run in the same direction.

Antiparallel Beta Sheet

Polypeptide chains run in opposite directions.

Fibrous Proteins

Long, thread-like proteins (e.g., collagen).

Globular Proteins

Compact, folded proteins (e.g., enzymes).

Protein Domains

Self-contained functional units within proteins.

Isoelectric Point (pI)

pH at which a protein carries no net charge.

Zwitterion

Molecule with both positive and negative charges but no net charge.

Electrophoresis

Movement of charged molecules in an electric field.

Gel Electrophoresis

Uses a gel matrix to separate proteins based on size and charge.

Capillary Electrophoresis

Uses thin capillary tubes for faster and more precise separation.

Polyacrylamide Gel Electrophoresis (PAGE)

Used for precise protein separation.

Isoelectric Focusing (IEF)

Separates proteins based on their isoelectric point (pI).

Continuous Buffer System

Same buffer throughout the gel and electrode chambers.

Discontinuous Buffer System

Different buffers in gel and electrode chambers, uses stacking gel.

Native Gel Electrophoresis

Proteins retain their natural shape, separated based on size, shape, and charge.

SDS-PAGE

Denaturing electrophoresis using SDS detergent, separates proteins based on size only.

Reducing Agents in SDS-PAGE

SDS and DTT break disulfide bonds to unfold proteins.

Detection Methods

Coomassie Blue Staining, Silver Staining, Radioactive Labeling.

Peptide Mapping

Digestion of proteins into peptide fragments for analysis.

Proteases in Peptide Mapping

Trypsin, Staphylococcus aureus V8, Clostridium histolyticum Arg-C, etc.

Western Blot

Technique for detecting specific proteins using antibodies.

Primary Antibody

Binds to the target protein.

Secondary Antibody

Binds to the primary antibody and is conjugated for detection.

Detection Systems

HRP (Horseradish Peroxidase), Alkaline Phosphatase (AP), Enhanced Chemiluminescence (ECL).

Southwestern Blot

Detects DNA-binding proteins using labeled DNA probes.

Far-Western Blot

Detects protein-protein interactions using proteins instead of antibodies.

2D-PAGE

Separates proteins first by charge (IEF) then by size (SDS-PAGE).