ENZYMES

Enzymes help with most chemical reactions in the body

Digestion requires Enzymes Amylase in salivary glands Pepsin in stomach Lipase and trypsin in small intestine

Enzyme supplements Aid in digestion

Enzymes assist in 2 main types of reactions in cells 1)Synthesis = Synthesize (make) compounds A + B  AB 2)Decomposition = Decompose (break) compounds CD  C + D These reactions require energy

Activation energy Energy required for a chemical reaction to occur

Most chemical reactions in cells occur too slowly for life to survive

Catalyst An inorganic chemical that lowers the activation energy so a reaction can occur

Enzymes Natural organic catalysts made of protein that lower the activation energy so a reaction can occur fast enough for cell to survive

Enzymes are very complex proteins Proteins are three dimensional

The shape of a protein determines its function Four levels of structure Primary structure – sequence of amino acids Secondary structure – alpha helix, beta pleated sheets Tertiary structure – Hydrogen bonds hydrophobic interactions, ionic bonds Quaternary structure – 2 or more poly peptides together

Primary structure

H bonds form secondary structure forms with peptide bonds

Tertiary structure forms from other bonds

Enzyme key Terms Enzyme – The protein that catalyzes a reaction Substrate - The molecule that the enzyme attaches to Active site - The spot on the enzyme that fits into the substrate

Substrates fit into enzymes

Enzyme helps reaction occur so substrate(s) forms the product

Enzymes and substrates have a specific fit Like a lock and key

Induced fit When active site adjusts to fit substrate Induced Fit and Hexokinase

Synthesis using enzyme A + B + Enzyme = AB + Enzyme

Decomposition using enzyme CD + Enzyme = C + D + Enzyme

Enzymes are not used up!!! Enzymes are on both sides of equation Enzymes can keep working! Unless denatured Heat, acid etc. can denature enzymes

Denaturing enzyme Heat etc. will break bonds of protein tertiary structure. Reversible Primary structure can stay intact

Enzyme animation Claymation enzyme 30 secs UpB0&feature=relatedhttp:// UpB0&feature=related Pacman Animation 2 mins OKreshttp:// OKres

Enzymes in industry Rennin used to manufacture cheese,

Paper industry Enzymes remove lignin to soften paper.lignin

Contact lenses Proteases clean lenses of proteinProteases

The enzyme catalase Peroxide kills cells cells have catalase to protect against peroxide Catalase breaks peroxide into water and oxygen gas H 2 O 2 + Enzyme  H O 2 + Enzyme

Enzyme Regulation Temperature pH Concentration of enzyme or substrate Inhibitors

Every enzyme has an optimal temperature

Effect of TEMPERATURE Increased temperature increases particle motion and enzyme reaction rate. BUT Enzymes are proteins and above a certain temperature they denature

Effects of pH Changes in pH also denature enzyme Change in pH can alter the active site and keep substrate from binding

Enzymes have an optimal pH Pepsin in stomach - acid Trypsin in intestine - base

Competitive inhibitor Blocks active site from substrate

Non Competitive inhibitor Attaches to enzyme in different place and alters its active site

Toxic substances are often enzyme inhibitors They stop important biological processes Ex cyanide, lead, mercury, pesticides

Allosteric enzymes Enzymes that can be altered by an non- competitive inhibitor A reaction product can act as a feedback inhibitor to slow enzyme. These can also be Promoters! That increase enzyme activity

Animations of enzymes m_2.htmhttp:// m_2.htm