The Effects of Ph and Salinity on Enzyme Function
Enzyme Activators and Inhibitors
Lucia House
AP Biology, Block 4
Mr. Trice
October 18, 2012
Introduction: Metabolism is the totality of all of an organism’s chemical reactions. Chemical reactions occur due to enzymes, a substance which acts as a catalyst in driving chemical reactions in order to produce a desired product (Campbell and Reece, 2002). A catalyst is usually a protein; however, some catalytic molecules counter this generalization. A discovery made in the early nineteen- nineties revealed that ribozymes, molecules made of ribonucleic acid (RNA), act as a catalyst in the transformation of an RAN molecule. Scientists concluded from the new discovery that the informational molecule RNA may have once been able to function without proteins (Dousti, 1995). However, enzymes are strictly proteins, and thus are subject to denaturation in certain conditions (Campbell and Reece, 2002).
1
Figure 1 Enzymes are granted the task of breaking bonds within the monomers of substrate, the molecule upon which the enzyme is acting. When the substrate and the enzyme bind, the substrate-enzyme complex is formed. The substrate binds to the enzyme’s active site, which is the part of the protein in which the enzyme fits. Scientists have introduced multiple models that attempt to illustrate exactly how the enzyme and substrate fit together (See figure 1). In the lock and key model, the substrate and enzyme fit together perfectly. In the induced fit model, however, the enzyme changes to fit the substrate, which secures the substrate-enzyme complex even further. Induced fit allows the enzyme to position the substrate so that its ability to catalyze is enhanced (Campbell and Reece, 2002). Once the enzyme has broken down or built up the reactant(s) and released the product(s), it bonds, unaffected, to another substrate (What are Enzymes?, 2010). In order for an enzyme to work efficiently, it must reduce the activation energy, or the initial energy input to start the
Lucia House
AP Biology, Block 4
Mr. Trice
October 18, 2012
Introduction: Metabolism is the totality of all of an organism’s chemical reactions. Chemical reactions occur due to enzymes, a substance which acts as a catalyst in driving chemical reactions in order to produce a desired product (Campbell and Reece, 2002). A catalyst is usually a protein; however, some catalytic molecules counter this generalization. A discovery made in the early nineteen- nineties revealed that ribozymes, molecules made of ribonucleic acid (RNA), act as a catalyst in the transformation of an RAN molecule. Scientists concluded from the new discovery that the informational molecule RNA may have once been able to function without proteins (Dousti, 1995). However, enzymes are strictly proteins, and thus are subject to denaturation in certain conditions (Campbell and Reece, 2002).
1
Figure 1 Enzymes are granted the task of breaking bonds within the monomers of substrate, the molecule upon which the enzyme is acting. When the substrate and the enzyme bind, the substrate-enzyme complex is formed. The substrate binds to the enzyme’s active site, which is the part of the protein in which the enzyme fits. Scientists have introduced multiple models that attempt to illustrate exactly how the enzyme and substrate fit together (See figure 1). In the lock and key model, the substrate and enzyme fit together perfectly. In the induced fit model, however, the enzyme changes to fit the substrate, which secures the substrate-enzyme complex even further. Induced fit allows the enzyme to position the substrate so that its ability to catalyze is enhanced (Campbell and Reece, 2002). Once the enzyme has broken down or built up the reactant(s) and released the product(s), it bonds, unaffected, to another substrate (What are Enzymes?, 2010). In order for an enzyme to work efficiently, it must reduce the activation energy, or the initial energy input to start the
Citations: Edition. San Francisco: Benjamin Cummings, publisher. 2002. p87-105. Print. Dousti, M