Enzyme Function and Characteristics PDF

Enzyme Function and Characteristics Enzyme Basics - Enzymes are biological catalysts that speed up chemical reactions. - They are typically proteins, but some are RNA molecules (ribozymes). - Enzymes lower the activation energy needed for reactions. Types of Enzymes 1. **Simple Proteins...

Enzyme Function and Characteristics Enzyme Basics - Enzymes are biological catalysts that speed up chemical reactions. - They are typically proteins, but some are RNA molecules (ribozymes). - Enzymes lower the activation energy needed for reactions. Types of Enzymes 1. **Simple Proteins** - Composed only of amino acids. 2. **Conjugated Proteins** - Contain a non-protein group (prosthetic group) that is essential for activity. - Example: Flavoproteins contain FAD (Flavin Adenine Dinucleotide). Properties of Enzymes - **Water Solubility**: Most enzymes are soluble in water. - **pH Dependence**: Activity can change with pH levels. - **Cofactors**: Non-protein molecules that assist enzyme function. - Example: Metal ions like zinc or magnesium. Mechanism of Action - Enzymes bind to substrates to form an enzyme-substrate complex. - The substrate is transformed into products. - The enzyme is released unchanged after the reaction. Activation Energy - The minimum energy required for a reaction to occur. - Enzymes reduce this energy barrier. Theories of Enzyme Action 1. **Lock and Key Theory** - The enzyme\'s active site (lock) is a perfect fit for the substrate (key). 2. **Induced Fit Theory** - The enzyme changes shape slightly to fit the substrate better upon binding. Examples of Enzymes - **Synthetases**: Enzymes that catalyze the synthesis of compounds. - **Ligases**: Enzymes that join two molecules together. - **Hydrolases**: Enzymes that catalyze the breakdown of compounds by adding water. Important Concepts - **Cofactors**: Essential for enzyme activity; can be metal ions or organic molecules. - **Prosthetic Groups**: Non-polypeptide units that are tightly bound to enzymes. - **Substrate**: The reactant that an enzyme acts upon. Summary Enzymes are crucial for biological processes, acting as catalysts that lower activation energy and increase reaction rates. Understanding their structure, function, and the factors affecting their activity is essential in biochemistry. Enzyme-Substrate Interaction Key Concepts - Enzymes and substrates have complementary structures, similar to a key fitting a lock. - When they bind, they form an enzyme-substrate complex, leading to a catalytic reaction. - After the reaction, the products are released from the enzyme. General Reaction 1. Formation of the enzyme-substrate complex: - E+S⇌ES*E*+*S*⇌*ES* 2. Conversion of the ES complex to products: - ES→P+E*ES*→*P*+*E* Example - **Sucrase and Sucrose:** 1. Sucrase+Sucrose⇌Sucrase-Sucrose ComplexSucrase+Sucrose⇌Sucrase-Sucrose Complex 2. Sucrase-Sucrose Complex→Glucose+FructoseSucrase-Sucrose Complex→Glucose+Fructose Koshland\'s Induced Fit Theory - The substrate must fit into the enzyme, but it can induce modifications in the enzyme or itself. - This binding leads to conformational changes that facilitate the reaction. Process 1. Substrate binds to a specific part of the enzyme. 2. This initial binding causes further interactions and changes in shape. 3. The enzyme\'s active site is adjusted to better fit the substrate. Factors Affecting Enzyme Activity 1. **Concentration of Enzymes and Substrates** 2. **Temperature** - Example: Lactase optimal at 57°C, Trypsin at 1.8°C. 3. **Presence of Cofactors** - Examples: Ferrous, Ferric, Magnesium. 4. **Inhibitors** - Antimetabolites like sulfanilamide can inhibit enzyme activity. 5. **Environmental Hazards** - Examples: - Mercury (HgHg) - Cadmium (CdCd) - Lead (PbPb) Nucleic Acids Biological Significance 1. Responsible for storing and transmitting genetic information. 2. Two main types of nucleic acids: - **DNA (Deoxyribonucleic Acid)** - Contains genetic material. - Exists primarily in a B-form under normal conditions. - **RNA (Ribonucleic Acid)** - Involved in protein synthesis. DNA Types - **A-DNA:** Formed under dehydrated conditions. - **B-DNA:** Most common form, right-handed helix. - **Z-DNA:** Left-handed helix, less common. Structure - Nucleotides consist of: - A phosphate group - A sugar (deoxyribose in DNA) - A nitrogenous base Sequence - The sequence of nucleotides encodes genetic information. Summary Understanding enzyme-substrate interactions and the role of nucleic acids is crucial for grasping biological processes and genetic information transmission. Nucleic Acids Overview - **Nucleic Acids**: Molecules that store and transmit genetic information. - Types: DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid). Structure of Nucleotides - **Nucleotide Components**: - **Sugar**: Ribose in RNA, Deoxyribose in DNA. - **Phosphate Group**: Provides the backbone. - **Nitrogenous Base**: - **Pyrimidines**: Cytosine (C), Thymine (T), Uracil (U). - **Purines**: Adenine (A), Guanine (G). Important Purines - **Adenine**: 6-aminopurine. - **Guanine**: 2-amino-6-oxypurine. - **Xanthine**: Metabolite found in tea and coffee. - **Theobromine**: Found in tea and cocoa. Central Dogma of Molecular Biology - **Processes**: 1. **Replication**: DNA to DNA. 2. **Transcription**: DNA to RNA. 3. **Translation**: RNA to Proteins. Transcription Process 1. **Initiation**: 1. RNA polymerase binds to a specific region of DNA. 2. Prepares to synthesize mRNA. 2. **Elongation**: 1. RNA polymerase adds nucleotides to the growing mRNA strand. 2. Complementary base pairing occurs (A with U, C with G). 3. **Termination**: 1. RNA polymerase reaches a stop sequence. 2. mRNA strand detaches from DNA. Inhibitors of RNA Synthesis - **Anticancer Drugs**: Target RNA synthesis. - **Rifampicin**: Used to treat tuberculosis and leprosy. Key Equations - **General Form**: - For a function: f(x)=p1+3x*f*(*x*)=*p*1+3*x*. - **Example of a Sequence**: - DNA template: 6:UACCUA6:*UACCUA*. Inheritance Concepts - **Recessive Inheritance**: Traits that require two copies of a gene to be expressed. - **Examples**: Ovarian function, heart defects. Summary Understanding the structure and function of nucleic acids is crucial for grasping genetic information flow in biological systems. The transcription process is a key step in gene expression, leading to protein synthesis. Carbohydrates Definition - Carbohydrates are organic compounds made of carbon (C), hydrogen (H), and oxygen (O). - General formula: Cn(H2O)n*Cn*​(*H*2​*O*)*n*​. - They provide energy and are essential for various biological functions. Storage Forms of Carbohydrates - **Starch**: Main storage form in plants. - **Glycogen**: Storage form in animals. Classification of Carbohydrates 1. **Monosaccharides**: Simple sugars. - Examples: - **Pentoses**: 5 carbon sugars (e.g., Ribose). - **Hexoses**: 6 carbon sugars (e.g., Glucose, Fructose). 2. **Oligosaccharides**: Short chains of monosaccharides. 3. **Polysaccharides**: Long chains of monosaccharides. - Examples: - **Starch**: Composed of glucose units. - **Glycogen**: Similar to starch but more branched. Types of Monosaccharides - **Tetroses**: 4 carbon sugars (e.g., Erythrose). - **Pentoses**: 5 carbon sugars (e.g., Ribose). - **Hexoses**: 6 carbon sugars (e.g., Glucose, Galactose). Epimers - Epimers are sugars that differ in configuration at only one specific carbon atom. - Example: Glucose and Galactose are epimers. Properties of Carbohydrates 1. **Physical Properties**: - Monosaccharides and oligosaccharides are typically white, crystalline solids. - They are soluble in water. Examples of Polysaccharides - **Starch**: Yields glucose upon hydrolysis (known as glucosan). - **Fructosan**: Yields fructose upon hydrolysis. Biological Significance - Carbohydrates play a crucial role in energy storage and supply. - They are involved in cell structure and signaling. Additional Notes - **Glycosaminoglycans (GAGs)**: Important for structural functions in the body. - Examples include Hyaluronic acid, Chondroitin sulfate, and Keratan sulfate. - **Heparin**: A GAG that acts as an anticoagulant. This summary provides a concise overview of carbohydrates, their classifications, properties, and biological significance. Study Notes on Carbohydrates and Related Concepts Optically Active Compounds - **Chiral Carbon**: A carbon atom attached to four different groups, leading to optical activity. - **Dextrarotatory**: Compounds that rotate plane-polarized light to the right, denoted as (d)(*d*). - **Levorotatory**: Compounds that rotate plane-polarized light to the left, denoted as (l)(*l*). Polysaccharides 1. **Amorphous Solid**: Polysaccharides do not have a defined structure. 2. **Low Molecular Weight**: They can form colloidal dispersions in water (H2OH2​O). 3. **High Molecular Weight**: Some are insoluble in water (e.g., cellulose). 4. **Taste**: Generally, they are not sweet and have no flavor. Chemical Properties Hydrolysis - **Definition**: The breakdown of compounds by water. - **Examples**: - Lactose: C12H22O11+H2O→glu+galC12​H22​O11​+H2​O→glu+gal - Sucrose: C12H22O11+H2O→glu+frC12​H22​O11​+H2​O→glu+fr - Cellulose: C6H10O5+H2O→2β−gluC6​H10​O5​+H2​O→2*β*−glu Agents of Hydrolysis 1. Heat 2. Acid 3. Bases 4. Enzymes Reducing Properties of Carbohydrates - **Definition**: Carbohydrates that can donate electrons due to a free aldehyde or ketone group. - **Tests**: - All reducing sugars are oxidized into acids, e.g., CHO→COOHCHO→COOH - **Fehling\'s Test**: Reduction is due to the reduction of cupric sulfate (CuSO4CuSO4​) to cuprous oxide. Fermentation - **Process**: Breakdown of complex substances by enzymes. - **Products**: Ethanol and carbon dioxide. - **Example**: C12H22O11+H2O→C2H5OH+C4H4O4C12​H22​O11​+H2​O→C2​H5​OH+C4​H4​O4​ Osazone Formation - **Reagent**: Phenylhydrazine. - **Result**: Formation of yellow crystals or precipitate. Glucose Transporters - **Function**: Facilitate the transport of glucose across cell membranes. Glycogen Storage Diseases - **Types**: - Liver forms (Type I, III, and VII) lead to increased glycogen storage. - **Symptoms**: Can affect muscles or other parts of the body. Carbohydrate Deficiencies - **Marasmus**: A condition due to carbohydrate deficiency leading to shrinkage. - **Insulin**: Regulates normal carbohydrate metabolism. Types of Diabetes Mellitus 1. **Type 1**: - Onset: Usually in childhood or adolescence. - Cause: Often due to viral infections (e.g., mumps). - Symptoms: Typically underweight. 2. **Type 2**: - Onset: Usually in late 20s to early 30s. - Cause: Often hereditary. 4 P\'s of Diabetes Mellitus 1. **Polydipsia**: Increased thirst. 2. **Polyuria**: Increased urination; urine has high specific gravity. 3. **Polyphagia**: Increased hunger. 4. **Persistence of Non-Healing Wounds**. Pathologies of Diabetes 1. **Neuropathy**: Affects nerve function, especially sensory nerves. 2. **Nephropathy**: Affects kidney function. 3. **Retinopathy**: Affects the retina, potentially leading to blindness. Summary - Carbohydrate deficiencies can lead to conditions like marasmus. - Diabetes Mellitus has two main types, each with distinct characteristics and complications. - The 4 P\'s are key symptoms to identify diabetes, and complications can significantly impact health. 0