BIOL 302 1nd Edition Lecture 7Outline of Previous Lecture I. Proteinsa. Quaternary structuresb. Self-assemblyc. AllosteryOutline of Current LectureProteins as EnzymesI. MechanismsII. Enzyme Kinetics III. Temperature IV. pHCurrent LectureProteins as Enzymesa. 3 Important Stepsi. Bind substrates/reactants (speeds up)ii. Facilitates the reactioniii. Releases productsb. Without enzymes there will be no life. As long as it stays in the cells, its ongoing. High specific (ex. Lock and Key Mechanism)c. Without it can cause the reaction to go way slower than with the enzymed. Substrate Binding Site i. RNASE: folding binds to RNA and cuts it, then degrades the RNAii. 3 essential parts: SER-123, THR-45, and the peptide bondiii. R group forms bonds with things. Proper R-groups are important! Proper and correct positioning is also important! Principal: R group reacting with substrate due to specificitye. What do enzymes do?i. Increases rate and probabilityThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.ii. Ex. Hydrolysis of Urea: protein and amino acid digestion. Bacteria that causes it to occur spontaneously at the rate of 1/106 years but once the enzyme (urrase) was added the new rate became 30,000 per second!I. Mechanismsa. Increases of local concentration of substrate and rate of reactionsb. Orbits substitutes in optimal positionc. Can participate in reactions  adds something into the reactiond. Binds transition states (unstable intermediate) of the enzyme i. Intermediates that are unstable are difficult to occur and uses energy of activatione. Hydrolysis of Peptide Bondsi. In presence of H20, the oxygen would attach to carbon and the –OH group is added due to the transition unstable state, the bonds become broken. Results of the 2 peptide bonds, hydrolyses the peptide bonds. R group is positioned very importantly so it can bind to stabilize the transition state – which reduces the activation energyII. Enzyme Kineticsa. How they behaveb. Propertiesi. When you started to add the substrate the rate and production increasesii. Eventually stops increasing (called plato) because it finally becomes saturatedc. Different enzymes have different Vmax (saturation amount) and KM (when you reach ½ of the saturation amount) – indication of the how efficiency the substrate is bounded to the enzymed. Higher the KM would be less effective. Low KM and low Vmax = more difficult of a reaction. Lower KM and high Vmax = most efficient. III. Temperaturea. 37 degrees C in body (regular body temperature) low temperature = low activityb. Cold  Hot = increases of the rate, it still requires energy from the heat. When it’s at it’s maximum heat then the protein begins to denature and hydrogen bonds begins falling apart (ex. Boiling an egg way too much would just denature the egg)c. Thermophiles: live under high temperatures, close to boiling. Their enzymes have been adapted to high temperatures. They have less hydrogen bonds and more covalent/cysteine bondsIV. pHa. Neutral (~7): most metabolic enzymes is at its peakb. Denatures because certain R-groups can be affective (ex. The ones that are acidicand basic). Putting a lot of hydroxyl groups can change bonding abilitie (eg. Pepsin: stomach, enzyme in the stomach that helps the aid in digestion