Enzymes Chapter 8

Learning Targets I can describe the structure and explain the significance and functions of enzymes in biological systems I can describe why an investment of activation energy is necessary to initiate a spontaneous reaction. I can explain how enzymes speed up chemical reactions. I can explain the interactions between substrates and active sites of enzymes. I can explain how the following affect enzymatic function: Enzyme and substrate concentrations pH, temperature and salinity coenzymes inhibition; competitive, non-competitive and allosteric cooperativity I can describe the role that enzymes play in feedback inhibition. I can design a lab that quantifiably measures the effect of an environmental factor on enzymatic activity.

Structure Protein Recall 4 levels of structure and bonds that hold them in place Substrate-specific: the active site is specifically shaped so only certain molecules fit on it

Learning Targets I can describe the structure and explain the significance and functions of enzymes in biological systems I can describe why an investment of activation energy is necessary to initiate a spontaneous reaction. I can explain how enzymes speed up chemical reactions. I can explain the interactions between substrates and active sites of enzymes. I can explain how the following affect enzymatic function: Enzyme and substrate concentrations pH, temperature and salinity coenzymes inhibition; competitive, non-competitive and allosteric cooperativity I can describe the role that enzymes play in feedback inhibition. I can design a lab that quantifiably measures the effect of an environmental factor on enzymatic activity.

Activation Energy How reactions work:

Learning Targets I can describe the structure and explain the significance and functions of enzymes in biological systems I can describe why an investment of activation energy is necessary to initiate a spontaneous reaction. I can explain how enzymes speed up chemical reactions. I can explain the interactions between substrates and active sites of enzymes. I can explain how the following affect enzymatic function: Enzyme and substrate concentrations pH, temperature and salinity coenzymes inhibition; competitive, non-competitive and allosteric cooperativity I can describe the role that enzymes play in feedback inhibition. I can design a lab that quantifiably measures the effect of an environmental factor on enzymatic activity.

Enzymes are Catalysts

Induced Fit Shape of active site can change slightly as substrate binds The active site is then molded into a precise conformation--sort of like a hand in a glove So, some enzymes can act on similar molecules, not just specific ones

Learning Targets I can describe the structure and explain the significance and functions of enzymes in biological systems I can describe why an investment of activation energy is necessary to initiate a spontaneous reaction. I can explain how enzymes speed up chemical reactions. I can explain the interactions between substrates and active sites of enzymes. I can explain how the following affect enzymatic function: Enzyme and substrate concentrations pH, temperature and salinity coenzymes inhibition; competitive, non-competitive and allosteric cooperativity I can describe the role that enzymes play in feedback inhibition. I can design a lab that quantifiably measures the effect of an environmental factor on enzymatic activity.

Enzyme-Substrate Interaction How do the following relate to enzymes? active site substrate induced fit energy of activation

Learning Targets I can describe the structure and explain the significance and functions of enzymes in biological systems I can describe why an investment of activation energy is necessary to initiate a spontaneous reaction. I can explain how enzymes speed up chemical reactions. I can explain the interactions between substrates and active sites of enzymes. I can explain how the following affect enzymatic function: Enzyme and substrate concentrations pH, temperature and salinity coenzymes inhibition; competitive, non-competitive and allosteric cooperativity I can describe the role that enzymes play in feedback inhibition. I can design a lab that quantifiably measures the effect of an environmental factor on enzymatic activity.

Enzyme-Substrate Concentration Enzymes act on one molecule at a time Reach a saturation point when all enzymes are engaged in reaction

pH, Temperature, Salinity All enzymes have a specific range for optimal performance Outside of that range  denature  don’t function

Denaturation

Inhibiting Factors Prevent/Interfere with Enzyme Function

Competitive Inhibition Competitive inhibitor has same shape as substrate (competes for active site) Prevents substrate from binding to active site by binding to active site itself

Allosteric Inhibition Inhibitor binds to allosteric site of enzyme Active site changes shape, no substrate binds

Enhancing Factors Help/Increase Enzyme Function

Cofactors & Coenzymes Cofactor assist with catalytic activities of enzyme Coenzyme is an organic cofactor Ex: vitamins

Allosteric Activation Change in the enzyme’s shape due to binding of activator at allosteric site Enzyme is stabilized by activator

Allosteric Cooperativity One substrate molecule primes an enzyme to receive more substrates readily Ex: hemoglobin

Learning Targets I can describe the structure and explain the significance and functions of enzymes in biological systems I can describe why an investment of activation energy is necessary to initiate a spontaneous reaction. I can explain how enzymes speed up chemical reactions. I can explain the interactions between substrates and active sites of enzymes. I can explain how the following affect enzymatic function: Enzyme and substrate concentrations pH, temperature and salinity coenzymes inhibition; competitive, non-competitive and allosteric cooperativity I can describe the role that enzymes play in feedback inhibition. I can design a lab that quantifiably measures the effect of an environmental factor on enzymatic activity.

Feedback Inhibition The switching off of a biochemical pathway by the product of the pathway Negative feedback Conserve energy!

Bozeman Enzymes Video

Learning Targets I can describe the structure and explain the significance and functions of enzymes in biological systems I can describe why an investment of activation energy is necessary to initiate a spontaneous reaction. I can explain how enzymes speed up chemical reactions. I can explain the interactions between substrates and active sites of enzymes. I can explain how the following affect enzymatic function: Enzyme and substrate concentrations pH, temperature and salinity coenzymes inhibition; competitive, non-competitive and allosteric cooperativity I can describe the role that enzymes play in feedback inhibition. I can design a lab that quantifiably measures the effect of an environmental factor on enzymatic activity.

AP Lab 13 Bozeman video