Overview of Macromolecules & Enzymatic Functions | Môn Food technology - Trường Đại học Quốc tế, Đại học Quốc gia Thành phố Hồ Chí Minh

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I. Macromolecules and Biological Function Macromolecule Monomer Major Functions Example Molecules
Carbohydrates Monosaccharides Energy, structure, Glucose, starch, recognition cellulose Proteins Amino acids
Catalysis, structure, Enzymes,
transport, regulation hemoglobin, collagen Lipids Glycerol + fatty Energy storage, Fats, oils, steroids acids membranes, hormones Nucleic Acids Nucleotides
Genetic information, DNA, RNA protein synthesis II. What Are Enzymes?
Enzymes are biological catalysts – mostly proteins – that speed up
biochemical reactions by lowering the activation energy required for a reaction to occur. lOMoAR cPSD| 58562220
Key Features of Enzymes:
● Specificity: Each enzyme is specific to one substrate or type of reaction.
● Reusability: Enzymes are not consumed in the reaction.
● Efficiency: They can increase reaction rates by millions of times.
III. Enzyme Structure and Function 1. Active Site
● The region on the enzyme where the substrate binds.
● Substrate: The molecule that the enzyme acts upon.
● Forms an enzyme-substrate complex → leads to product formation.
2. Lock and Key Model vs. Induced Fit
● Lock and Key: Substrate fits exactly into the enzyme.
● Induced Fit: Enzyme changes shape slightly to accommodate substrate.
IV. Enzyme Classification
Enzymes are grouped into six classes based on the type of reaction they catalyze: Class Name Function Number 1
Oxidoreductase Transfer of electrons s (oxidation/reduction) 2 Transferases
Transfer functional groups 3 Hydrolases
Hydrolysis reactions (add water to break bonds) 4 Lyases
Break bonds without hydrolysis 5 Isomerases Rearrangement of atoms 6 Ligases
Join molecules together using ATP
V. Allosteric Regulation of Enzymes lOMoAR cPSD| 58562220
Some enzymes have an additional site called the allosteric site, separate from the active site. Types of Regulation:
● Allosteric Activator: Binds to allosteric site and increases enzyme activity.
● Allosteric Inhibitor: Binds to allosteric site and decreases activity.
This regulation is common in enzymes involved in metabolic pathways. VI. Enzyme Inhibition
1. Competitive Inhibition ●
Inhibitor binds directly to the active site. ●
Competes with the substrate. ●
Can be overcome by increasing substrate concentration.
2. Non-competitive Inhibition ●
Inhibitor binds to an allosteric site, not the active site. ●
Changes the enzyme’s shape, reducing activity. ● Cannot be
reversed by adding more substrate. 3. Irreversible Inhibition lOMoAR cPSD| 58562220 ●
Inhibitor binds permanently (often covalently) to enzyme. ●
Enzyme becomes permanently inactive.
VII. Cofactors and Coenzymes
What Are Cofactors and Coenzymes?
Cofactors and coenzymes are non-protein helper molecules that assist
enzymes in performing their biological functions. Analogy:
An enzyme is like a machine. Cofactors and coenzymes are the
tools it needs to function properly.
1. Types of Enzyme Helpers a. Cofactors ●
Inorganic substances (no carbon-hydrogen bonds) Metal Ion Role in Enzyme Zn²
DNA polymerase, carbonic anhydrase Fe² / Fe ³
Cytochromes (electron transport) Mg²
ATP-using enzymes (kinases) Cu² Cytochrome c oxidase Mn²
Arginase, superoxide dismutase ●
Stabilize enzyme structure ●
Participate in redox reactions ●
Help bind substrate to the active site ●
Typically metal ions 📌 Examples: lOMoAR cPSD| 58562220 🔧 Function: lOMoAR cPSD| 58562220 b. Coenzymes ●
Organic molecules (contain carbon) ●
Often derived from vitamins Coenzyme Derived From Function (V itamin) NAD / NADP Niacin (B3) Electron carrier in redox reactions FAD / FMN Riboflavin (B2) Electron carrier Coenzyme A
Pantothenic acid (B5) Transfers acyl groups (e.g., in TCA cycle) TPP (Thiamine Thiamine (B1)
Decarboxylation of alpha-keto pyrophosphate) acids Biotin Biotin (B7) CO tra nsfer (carboxylation) PLP (Pyridoxal Vitamin B6
Transamination reactions phosphate)
3 . Apoenzyme vs Holoenzyme Term Meaning Apoenzyme
Enzyme without its cofactor/coenzyme (inactive) Holoenzyme
Enzyme with cofactor/coenzyme bound (active) ●
Loosely or tightly bound to enzyme 📌 Examples: lOMoAR cPSD| 58562220 🔧 Function: ●
Act as carriers of chemical groups (electrons, acyl
groups, CO )₂ ● Participate directly in catalysis
🔁 A cofactor or coenzyme must bind to make the enzyme functional. lOMoAR cPSD| 58562220
4. Classification of Cofactors
Cofactors can be divided into: Category Subtype Examples Inorganic Metal ions Fe² , Zn² , M g² Organic Coenzymes NAD , CoA, FAD
Organic (tightly bound)
Prosthetic groups Heme in cytochromes
5. Role in Enzymatic Reactions
Cofactors and coenzymes often: ●
Help orient the substrate ●
Participate in electron or group transfer ●
Allow oxidation-reduction reactions ●
Serve as intermediates in multi-step processes VIII. Enzyme Kinetics
Kinetics deals with the rate of enzymatic reactions and how different factors affect this rate.
Factors Affecting Enzyme Activity: 1.
Substrate concentration: More substrate → faster reaction (until saturation). 2.
Enzyme concentration: More enzyme → faster rate. 3.
Temperature: Increases rate until denaturation. lOMoAR cPSD| 58562220
4. pH: Each enzyme has an optimal pH.
5. Inhibitors: Reduce enzyme activity.
IX. Metabolism Overview Definition:
Metabolism = all chemical reactions in the body, including energy production,
synthesis, and breakdown of molecules.
Divided into two categories: 1. Catabolism (Breakd ) own ●
Large molecules → smaller ones ● Releases energy (ATP) ● Examples: ○ Glycolysis ○
Citric Acid Cycle (CAC or TCA or Krebs cycle)
2 . Anabolism (Synthesis ) ●
Builds large molecules from small ones ● Requires energy ●
Examples: protein synthesis, DNA replication
Vitamins, Minerals, and Their Role in Enzyme Function
What Are Vitamins and Minerals? Vitamins ●
Organic compounds (contain carbon) ●
Required in small amounts for normal metabolic functions ●
Cannot be synthesized (or not in sufficient quantities) by the body →
must be obtained from diet lOMoAR cPSD| 58562220
🔍 Many vitamins serve as coenzymes or are precursors to coenzymes. lOMoAR cPSD| 58562220 lOMoAR cPSD| 58562220 Minerals ●
Inorganic elements (do not contain carbon) ●
Needed in small amounts ●
Cannot be synthesized → obtained through food and water
Many minerals serve as cofactors for enzymes or are structural components. Key Definitions E nzyme
A biological catalyst (mostly proteins) that speeds up chemical reactions without being consumed. Co factor
A non-protein helper required by some enzymes for activity. Two types: 1.
Inorganic → e.g., metal ions like Fe², Zn² , M g² 2.
Organic (coenzymes) → derived from vitamins Co enzyme
A specific type of organic cofactor, usually derived from vitamins, that assists enzyme function by: ●
Accepting or donating atoms ●
Transferring chemical groups
Without their cofactors/coenzymes, many enzymes cannot function properly.
Examples of Vitamin-Derived Coenzymes Vitamin Coenzyme Form Function in Enzyme Example Enzyme Reaction B1 TPP (Thiamine Transfers aldehyde Pyruvate Thia ( mine ) Pyrophosphate) groups dehydrogenase B2 FAD/FMN Electron transfer Succinate ( Riboflavin ) ox ( idation-reduction ) dehydrogenase lOMoAR cPSD| 58562220 B3 (Niacin) NAD / NADP⁺ ⁺ Electron transfer in Lactate metabolism dehydrogenase B5
Coenzyme A (CoA) Acyl group transfer Acetyl-CoA synthetase (Pantothenic acid) B6 PLP (Pyridoxal
Amino acid metabolism Transaminase (Pyridoxine) phosphate) B7 (Biotin) Biotin CO transfer ₂ Acetyl-CoA (carboxylation) carboxylase B9 (Folate) THF Transfers one-carbon Thymidylate (Tetrahydrofolate) units synthase B12 Methylcobalamin Methyl group transfer Methionine (Cobalamin) synthase lOMoAR cPSD| 58562220
🔹 Examples of Mineral Cofactors lOMoAR cPSD| 58562220 Mineral Function Example Enzyme Fe² / Fe³
Electron transfer in redox reactions ⁺ ⁺ Cytochromes, (Iron) catalase Zn² (Zinc)⁺
Stabilizes enzyme structure, Carbonic anhydrase catalytic role Mg²
Stabilizes ATP, enzyme activation DNA polymerase ⁺ (Magnesium) Mn² Superoxide dismutase ⁺
Cofactor in metabolism and (Manganese) antioxidant enzymes
Cu² (Copper)⁺ Electron transport, redox reactions Cytochrome c oxidase Ca² ⁺
Signal transduction, muscle Calmodulin-regulated (Calcium) contraction kinases
Se (Selenium) Antioxidant function Glutathione peroxidase lOMoAR cPSD| 58562220
How Do Vitamins and Minerals Help Enzymes? Activation
They enable or enhance the catalytic power of enzymes by participating
directly in the reaction mechanism.
Transfer of Groups or Electrons
Many coenzymes derived from vitamins carry atoms or electrons from one
molecule to another in metabolic pathways. Structural Support
Some minerals (like Zn²) s
tabilize enzyme structure, allowing proper folding
and active site formation.
Real-Life Example: Glycolysis and the TCA Cycle
Glycolysis and the TCA Cycle (both seen in your whiteboard image) require: ●
NAD / FAD → derived from Vitamin B3 and B2 ●
CoA → from Vitamin B5 ● Mg² →
essential for enzymes using ATP
Without these micronutrients:
Enzymes would be inactive → metabolism would halt → no energy → cell death
Deficiency Consequences Deficiency Effect on Enzymes Symptoms Niacin (B3) ↓ NAD , po or metabolism
Pellagra (diarrhea, dermatitis, dementia) Thiamine (B1)
↓ TPP, impaired glucose
Beriberi (muscle weakness, oxidation nerve damage) lOMoAR cPSD| 58562220 Iron
↓ Cytochrome activity Anemia, fatigue Zinc ↓ DNA/RNA synthesis Poor wound healing, growth retardation Final Notes
● Enzyme activity is dependent on the availability of vitamins and minerals.
● Many metabolic disorders result from deficiencies in these micronutrients.
● Always consider enzyme–cofactor and enzyme–coenzyme
interactions when studying metabolism or enzymatic regulation.
Enzymes and Their Roles in Metabolizing Carbohydrates, Proteins, and Lipids 🧩 Overview
Enzymes are biological catalysts that speed up the chemical breakdown and
transformation of macromolecules. Each group of macromolecules
(carbohydrates, proteins, lipids) has specific enzymes that help in their digestion and metabolism.
💡 Enzymes are substrate-specific: each works on a specific type of molecule.
1. 🔹 Enzymes Acting on Carbohydrates
🧬 Target: Polysaccharides and Disaccharides lOMoAR cPSD| 58562220
Carbohydrates are broken down into monosaccharides (e.g., glucose) that
cells can absorb and use for energy. 🔬 Key Enzymes: Enzyme Source Substrate Product Amylase Saliva, pancreas Starch Maltose (disaccharide) (polysaccharides) Maltase Small intestine Maltose Glucose lOMoAR cPSD| 58562220 Lactase Small intestine Lactose Glucose + Galactose Sucrase Small intestine Sucrose Glucose + Fructose ETC) to produce ATP. ●
Enzymes regulate the rate of glucose breakdown.
2 . Enzymes Acting on Proteins Target: Polypeptides
Proteins are broken into amino acids, which are used for tissue building, Enzyme Source Substrate Product Pepsin Stomach (acidic) Proteins Peptides Trypsin
Pancreas (alkaline) Peptides Shorter peptides Chymotrypsin Pancreas Peptides Shorter peptides Peptidase Small intestine Peptides Amino acids
3 . Enzymes Acting on Lipids
📌 Role in Metabolism: lOMoAR cPSD| 58562220
● Glucose is then used in cellular respiration (glycolysis → TCA cycle →
repair, and energy (in starvation). 🔬 Key Enzymes:
📌 Role in Metabolism:
● Amino acids are used for protein synthesis or converted into
intermediates in the TCA cycle for energy (deamination).
🧬 Target: Triglycerides and phospholipids
Lipids are broken into fatty acids and glycerol for energy storage or cellular membrane synthesis. 🔬 Key Enzymes: