Ch. 5 Enzyme Activity Flashcards
Catchol oxidase
Enzyme (speeds up reaction)
- potato juice
Benzoquinone
Product of normal reaction
Injury is to the plant cells mixes two substances and results. As seen in the brown color of the cut surfaces of potatoes, apples, and bananas.
- is believed to inhibit the growth of certain microorganisms that cause plant tissue to rot
Ex: apple turning brown after you bite into it
Hydroquinone
- Inhibitor + permanent binder of catechol oxidase
- shape resembling catechol
- permanently binds to catechol oxidase and inhibits the enzyme
- Substance with a molecular shape closely resembling that of catechol
Catechol
Substrate
Substrates
Substances at the beginning of a reaction
Products
The substrates that are left at the end of the reaction
of substrates and products vary among reactions
Enzymes
Molecules that function as catalysts
(Any substances that changes the rate of a chemical reaction by a catalyst)
• each has specific substrates that it can chemically recognize, bind, and modify in certain ways.
A complex structure gives an enzyme ______
A specific shape
Active site
Has a shape and chemistry that fits to the substrate molecules
(Reactions dont permanently change or use up enzyme molecules so that the enzyme can be used repeatedly)
Denaturation
Most enzymes are complex protein molecules with specific shapes. Weak hydrogen bonds hold the molecule together and can be broken fairly easily. The resulting change in the 3D shape
-temperature or PH can cause this
Inhibitor
An enzyme can sometimes complex (though a little less effectively) with a molecule that is similar in shape to its normal substrate. If the substrate fails to release after binding, it is described at this
Cofactors
- Nonprotein molecules
- metal ions
part of enzymes active site
Phenylthiourea (PTU)
Trace amounts of copper are present in the potato extract used in these experiments.
- toxic substance
- binds strongly to copper = makes copper available to enzymes
