ENZYMES

ENZYME STRUCTURE

ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes do not change when they perform their function, and can be used over & over again. Enzymes do not change when they perform their function, and can be used over & over again. hill.com/sites/ /student_view0/chapter2/an imation__how_enzymes_work.html hill.com/sites/ /student_view0/chapter2/an imation__how_enzymes_work.html hill.com/sites/ /student_view0/chapter2/an imation__how_enzymes_work.html hill.com/sites/ /student_view0/chapter2/an imation__how_enzymes_work.html The shape of an enzyme determines its function The shape of an enzyme determines its function Their structure can be changed due to environmental factors and made inactive (denatured). Their structure can be changed due to environmental factors and made inactive (denatured).

ACTIVATION ENERGY Enzymes lower activation energy. (the energy required to make a chemical reaction occur). Enzymes lower activation energy. (the energy required to make a chemical reaction occur). content/enzymes/enzymes.html content/enzymes/enzymes.html content/enzymes/enzymes.html content/enzymes/enzymes.html essentialchemistry/flash/activa2.swf essentialchemistry/flash/activa2.swf essentialchemistry/flash/activa2.swf Exergonic reactions- these release energy Exergonic reactions- these release energy Endergonic reactions- these absorb free energy Endergonic reactions- these absorb free energy Energy coupling- the use of an exergonic process to drive an endergonic reaction. Ex: formation of ATP, from ADP. ATP is biological energy. Energy coupling- the use of an exergonic process to drive an endergonic reaction. Ex: formation of ATP, from ADP. ATP is biological energy.

THEORIES Lock and Key- One specific enzyme fits into one specific substrate. Lock and Key- One specific enzyme fits into one specific substrate. ce/labbench/lab2/binding.html ce/labbench/lab2/binding.html ce/labbench/lab2/binding.html ce/labbench/lab2/binding.html Induced fit- the enzyme fits to form the substrate. Induced fit- the enzyme fits to form the substrate.

ENZYME Enzymes are very specific, they can only help one reaction. Enzymes are very specific, they can only help one reaction. tions/Enzyme%20activity.html tions/Enzyme%20activity.html tions/Enzyme%20activity.html tions/Enzyme%20activity.html Some enzymes can be used repeatedly on the same set of molecules to build long chains. Some enzymes can be used repeatedly on the same set of molecules to build long chains.

FACTORS AFFECTING ENZYMES Certain enzymes work in a specific pH. Certain enzymes work in a specific pH. Enzyme%20activity.html Enzyme%20activity.html Enzyme%20activity.html Enzyme%20activity.html

FACTORS Cont… Enzymes work in specific temperatures. As temperature increases, enzyme activity increases unless it is too high, then it becomes denatured or destroyed. Enzymes work in specific temperatures. As temperature increases, enzyme activity increases unless it is too high, then it becomes denatured or destroyed.

FACTORS Cont… Small amounts of enzymes can react to a lot of substrate, but can limit the rate of the reaction, but does not decrease the reaction. Small amounts of enzymes can react to a lot of substrate, but can limit the rate of the reaction, but does not decrease the reaction. Large amounts of enzymes will increase the reaction. Large amounts of enzymes will increase the reaction.

COENZYMES & COFACTORS These are not proteins. It is a coenzyme (ex. Vitamins) if it is an organic molecule and a cofactor if it is inorganic. This allows a reaction to take place. They maybe bound tightly to the active site permanently or bond loosely along with the substrate. These are not proteins. It is a coenzyme (ex. Vitamins) if it is an organic molecule and a cofactor if it is inorganic. This allows a reaction to take place. They maybe bound tightly to the active site permanently or bond loosely along with the substrate.

Enzyme Inhibitors Some chemicals inhibit the action of specific enzymes and is usually irreversible. Some chemicals inhibit the action of specific enzymes and is usually irreversible. Noncompetitive inhibitors- these do not compete directly with the active site. They impede enzymatic reactions by binding to another part of the enzyme. This will cause the enzyme to change shape and less active. Noncompetitive inhibitors- these do not compete directly with the active site. They impede enzymatic reactions by binding to another part of the enzyme. This will cause the enzyme to change shape and less active. inan.htm inan.htm inan.htm inan.htm

Enzyme Inhibitors cont… competitive Inhibitors- these chemicals reduce the productivity of enzymes by blocking the substrate from entering the active site. competitive Inhibitors- these chemicals reduce the productivity of enzymes by blocking the substrate from entering the active site /animations/enzyme.swf /animations/enzyme.swf /animations/enzyme.swf /animations/enzyme.swf inhban.htm inhban.htm inhban.htm inhban.htm 8/student/animations/enzyme_inhibition/enzym e_inhibition.swf 8/student/animations/enzyme_inhibition/enzym e_inhibition.swf 8/student/animations/enzyme_inhibition/enzym e_inhibition.swf 8/student/animations/enzyme_inhibition/enzym e_inhibition.swf

Allosteric Regulation Some regulatory molecules behave like reversible noncompetitive inhibitors. These molecules bind to an allosteric site, which may either inhibit or stimulate the enzymes activity. Some regulatory molecules behave like reversible noncompetitive inhibitors. These molecules bind to an allosteric site, which may either inhibit or stimulate the enzymes activity. zymes/allosteric.swf zymes/allosteric.swf zymes/allosteric.swf zymes/allosteric.swf

Feedback Inhibition When metabolic pathways are switched off by an end-product. When metabolic pathways are switched off by an end-product. y1111/animations/enzyme.swf y1111/animations/enzyme.swf y1111/animations/enzyme.swf y1111/animations/enzyme.swf

Cooperativity Molecules may stimulate the catalytic powers of an enzyme. If an enzyme has two or more subunits, this interaction with one substrate molecule triggers the same favorable conformational change in all the subunits of the enzyme. Molecules may stimulate the catalytic powers of an enzyme. If an enzyme has two or more subunits, this interaction with one substrate molecule triggers the same favorable conformational change in all the subunits of the enzyme. y1111/animations/enzyme.swf y1111/animations/enzyme.swf y1111/animations/enzyme.swf y1111/animations/enzyme.swf