ENZYMES Introduction 􀁡enzymes are proteins 􀁡enzymes are catalysts 􀁠speed up a chemical reaction by lowering the activation energy required 􀁡thousands of enzymes in cells 􀁠catechol oxidase will be tested

Factors that Affect Enzyme Activity Factors that Affect EnzymeActivity for catechol oxidase 􀁡specificity 􀁠ability to discriminate between similar structures 􀁡temperature􀁠optimally, 40 C 􀁡pH􀁠optimally, pH 7 􀁡cofactors􀁠Cu++ (metallic ions

Enzyme Structure and Function 􀁡Enzyme (catechol oxidase in potato extract)􀁠active site􀁠allosteric site 􀁡substrate (catechol) binds to active

Enzyme Structure and Function, cont substrate and enzyme (lactose) (lactase) enzyme-substrate complex Products (glucose)

Specificity Procedure 􀁠tube L (enzyme + Lactose)) 􀁠tube M (enzyme + Maltose) 􀁡 place tubes in 40 0C 􀁡Which tube shows more product formed

Temperature Procedure 􀁡place enzyme in appropriate temp. for 5 min before testing 􀁠tube at 5 0C tube at 25 0C􀁠tube at 40 0C tube at 60 0C􀁠tube at 80 0C and tube at 100 0C 􀁡􀁡Which tube shows most product formed

pH 􀁡Procedure 􀁡Place enzyme in appropriate buffer for 5 min before testing, place 40 0C 􀁠tube at pH 2 tube, at pH 4,􀁠tube at pH 6 tube at pH 7,pH 8,􀁠tube at pH 10 tube at pH 12 􀁡􀁡Which tube shows most product formed?

Cofactors 􀁡place tubes in 40 0C 􀁠tube C (enzyme + water + milksubstrate) 􀁠tube E (enzyme + EDTA + milksubstrate) 􀁡􀁡Which tube shows product formed? 􀁡*PTU (phenylthiourea is poisonous), Dispose in labeled containers