Proteins: Structure, Functions, and Denaturation

Study Notes

Proteins

Structure:
- Primary structure: sequence of amino acids
- Secondary structure: α-helix, β-pleated sheet, and random coil
- Tertiary structure: 3D shape of a protein
- Quaternary structure: arrangement of subunits
Functions:
- Enzymes: catalyze reactions
- Transport: transport molecules and ions
- Storage: store and release molecules
- Regulation: regulate metabolic pathways
- Defense: immune system proteins
Denaturation:
- Unfolding of protein structure
- Caused by heat, pH, and chemicals
- Loss of biological function

Lipid Metabolism

Fatty Acid Oxidation:
- β-Oxidation: breakdown of fatty acids into acetyl-CoA
- Electron transport chain: generation of ATP
Fatty Acid Synthesis:
- De novo synthesis: synthesis of fatty acids from acetyl-CoA
- Fatty acid synthase complex: enzyme complex involved
Triacylglycerol Metabolism:
- Triacylglycerol synthesis: esterification of glycerol and fatty acids
- Lipolysis: breakdown of triacylglycerols into fatty acids and glycerol

Enzymology

Characteristics:
- High specificity for substrates
- Optimal temperature and pH
- Inactivation by denaturation
Kinetics:
- Michaelis-Menten equation: describes enzyme-substrate interaction
- Km: Michaelis constant, measure of enzyme-substrate affinity
- Vmax: maximum reaction rate
Inhibition:
- Competitive inhibition: inhibitor binds to active site
- Non-competitive inhibition: inhibitor binds to allosteric site
- Uncompetitive inhibition: inhibitor binds to enzyme-substrate complex

Metabolic Pathways

Glycolysis:
- Breakdown of glucose into pyruvate
- Anaerobic: no oxygen required
- Produces ATP and NADH
Citric Acid Cycle (Krebs Cycle):
- Breakdown of acetyl-CoA into CO2
- Produces ATP, NADH, and FADH2
- Electron transport chain: generates ATP
Pentose Phosphate Pathway:
- Generation of NADPH and pentoses
- Important for nucleic acid synthesis and antioxidant defense

Proteins

Primary structure of a protein is the sequence of amino acids
Secondary structure includes α-helix, β-pleated sheet, and random coil
Tertiary structure refers to the 3D shape of a protein
Quaternary structure is the arrangement of subunits

Protein Functions

Enzymes catalyze reactions
Transport proteins transport molecules and ions
Storage proteins store and release molecules
Regulatory proteins regulate metabolic pathways
Defense proteins are involved in the immune system

Denaturation

Unfolding of protein structure resulting in loss of biological function
Caused by heat, pH, and chemicals

Lipid Metabolism

Fatty acid oxidation involves β-oxidation, breaking down fatty acids into acetyl-CoA
Electron transport chain generates ATP during fatty acid oxidation

Fatty Acid Synthesis

De novo synthesis involves the synthesis of fatty acids from acetyl-CoA
Fatty acid synthase complex is the enzyme complex involved in fatty acid synthesis

Triacylglycerol Metabolism

Triacylglycerol synthesis involves the esterification of glycerol and fatty acids
Lipolysis breaks down triacylglycerols into fatty acids and glycerol

Enzymology

Enzymes have high specificity for substrates
Enzymes have optimal temperature and pH
Enzymes can be inactivated by denaturation

Enzyme Kinetics

Michaelis-Menten equation describes enzyme-substrate interaction
Km represents the Michaelis constant, a measure of enzyme-substrate affinity
Vmax represents the maximum reaction rate

Enzyme Inhibition

Competitive inhibition occurs when an inhibitor binds to the active site
Non-competitive inhibition occurs when an inhibitor binds to an allosteric site
Uncompetitive inhibition occurs when an inhibitor binds to the enzyme-substrate complex

Metabolic Pathways

Glycolysis breaks down glucose into pyruvate
Glycolysis is an anaerobic process, requiring no oxygen
Glycolysis produces ATP and NADH

Citric Acid Cycle (Krebs Cycle)

Citric acid cycle breaks down acetyl-CoA into CO2
Citric acid cycle produces ATP, NADH, and FADH2
Electron transport chain generates ATP during citric acid cycle

Pentose Phosphate Pathway

Pentose phosphate pathway generates NADPH and pentoses
Pentose phosphate pathway is important for nucleic acid synthesis and antioxidant defense

Types of Kidney Stones Overview of different types of kidney stones (e.g., calcium oxalate, uric acid, struvite, cystine) Brief description of each type and their prevalence

Description

Understand the structure of proteins, including primary, secondary, tertiary, and quaternary structures, and their various functions such as enzymes, transport, storage, regulation, and defense. Learn about protein denaturation and its effects.