Enzymes and Catalysis

Enzymes and Catalysts

• Catalysts are chemicals increasing the rate of chemical reactions enabling them to occur at lower temperatures (or energy) without being consumed.
• Catalysts provide an alternate reaction pathway, lowering the energy required for reactions.
• Enzymes are protein catalysts found in living organisms
• Enzymes have an active site, which is the specific region where the substrate (the substance being reacted) binds.
• The substrate sucrose is made up of glucose and fructose bonded together
• The substrate binds to the enzyme, creating an enzyme-substrate complex.
• The enzyme and substrate binding places stress on glucose-fructose bond, causing it to break.
• Products get released, and the enzyme is able to bind to other substrates.

Factors affecting enzyme reactions

• Specific enzymes function best within a specific pH range.
• Enzymes in blood function best at a pH of 7.2-7.4.
• Stomach enzymes function best at a pH of 1.0-2.0.
• Denaturing destroys a protein's or other biological macromolecule's characteristic properties through heat, acidity, or other disruptions, ultimately changing its molecular conformation.
• Increased temperatures increase enzyme activity until the enzyme denatures.
• Very high temperatures break down proteins, rendering enzymes ineffective.
• Increased substrate concentrations typically lead to greater enzyme activity until all active sites are occupied.

Competitive Inhibitors and Enzyme Regulation

• Molecules with a similar shape to the substrate can bind to the active site of an enzyme, preventing the desired reaction.
• Carbon monoxide (CO) acts as a competitive inhibitor by binding to red blood cells and hindering oxygen binding.
• Feedback inhibition is the process where the final product inhibits an enzyme in the metabolic pathway.
• Metabolism's three main purposes include converting food into energy for cellular processes, converting food into building blocks for proteins, lipids, nucleic acids, and carbohydrates, and eliminating nitrogenous wastes.
• Cofactors are inorganic ions that support enzymes in combining with substrate molecules, obtained from mineral supplements, like iron helping oxygen bind.
• Coenzymes are organic molecules that help enzymes combine with substrate molecules and come from vitamins.

Nutrients

• Good nutrition is required for a healthy and disease-resistant human body
• Nutrients include carbohydrates, lipids, proteins, vitamins, minerals, and nucleic acids
• Carbohydrates, built from sugar, fuel cellular respiration with energy and form plant cell walls structurally.
• Lipids, fat-based molecules, store large energy and form cell membranes structurally.
• Proteins, polypeptide chains, store energy; they provide building blocks structurally for cells and make enzymes.
• Vitamins are organic molecules that help mediate enzyme actions and are also called coenzymes.
• Minerals, inorganic molecules, facilitate enzyme activities and are also called cofactors.
• Nucleic acids form DNA, RNA, and ATP.

General Types of Molecules

• Polymers are compounds of two or more subunits, often linked by dehydration synthesis.
• Monomers are compounds of single subunits, which can be produced by hydrolysis of polymers.
• Carbohydrates are either single unit sugar molecules called monosaccharides, two unit sugar molecules called disaccharides, or multiple unit sugar molecules called polysaccharides.
• Sugar molecules consist of subunits, either a 6-ring (hexose) or 5-ring (pentose) base structure.
• Monosaccharides are simple single sugars composed of 5-unit monomers (pentoses) or 6-unit polymers (hexoses)
• Disaccharides and polysaccharides come from dehydration synthesis of monomers, forming a saccharide bond after water molecules are removed.
• Polysaccharides are complex carbohydrates such as glycogen, starch, or cellulose.
• Benedicts test detects reducing sugars turning from blue to orange/red, while the Starch test detects starch forming a blue-black iodine starch complex.
• Lipids are non-polar, water-insoluble, high-energy molecules composed of glycerol and fatty acids, combining by dehydration synthesis.
• Saturated fats lack double bonds in their carbon chain, have maximum hydrogen atoms, and stay solid at room temperature because they are unreactive.
• Unsaturated fats have at least one double bond in their carbon chain allowing liquid form at room temperature and are more reactive
• To test for Lipids, Translucence is tested on paper where if lipids are present and will cause paper to become translucent.
• Sudan IV test is where lipids will dissolve in the Sudan IV turning into a red paste.
• Proteins are polymers of 20 different amino acids joined by dehydration synthesis and held together by peptide bonds, forming structural components of cells, enzymes, and useful energy stores.
• All amino acids have a basic amino group and carboxylic acid.
• Different amino acids have different R groups or side chains with 20 amino acids in total.
• Proteins form from long amino acid chains, linked by peptide bonds through dehydration synthesis

Protein Structures

• Hydrogen bonds cause proteins to fold into pleated sheets or coil into helixes
• Further polypeptide folding creates a larger globular structure
• Quaternary structure represents large globular proteins with two or more interacting polypeptides.
• Biuret test indicates proteins are present when the reagent turns purple.
• Coagulation happens when excessive heat, radiation, or pH changes break down hydrogen bonds in proteins, and if it's irreversible, it's considered coagulation.

Mineral and Vitamin Deficiencies, High Fat Diets, High Sugar Diets

• Anemia results from iron-deficient diets, leading to low blood oxygen, tiredness, and low energy, common in menstruating females or those on vegan diets
• Vitamin C deficiency leads to scurvy, causing rashes, loose teeth, painful joints/muscles, low energy, and appetite loss; citrus fruit provides high content of Vitamin C
• High-fat diets can elevate cholesterol levels, leading to plaque buildup in blood vessels, potentially resulting in atherosclerosis, high blood pressure, heart disease, and heart attacks.
• High-sugar diets, especially those with refined sugars, can lead to excessive weight gain as the body stores the extra sugar as glycogen and fats.
• High sugar diets can increase developing Type II diabetes, resulting in improper use of insulin.