Temperature Effects on Enzymes

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Enzymes are proteins that speed up a chemical reaction. In other words they act as organic catalysts. Another importan fact is that enzymes are not being used in the reaction, thus, it can be reused over and over again. In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, the products. Enzymes work by lowering the activation energy.Most enzyme reaction rates are millions of times faster than those of comparable uncatalyzed reactions. Enzymes are very specific, that is the enzyme will only work on the substrate that fits the active site and no other. For example, the enzyme we used in lab, cathechol oxidase, works only on the substrate catechol. Beacuse the enzymes are so specific they will only affect one direction of the reaction.

Each enzyme works within quite a small pH range. There is a pH at which its activity is greatest (the optimal pH). This is because changes in pH can make and break intra- and intermolecular bonds, changing the shape of the enzyme and, therefore, its effectiveness.

Some substances reduce or even stop the catalytic activity of enzymes in biochemical reactions. They block or distort the active site. These chemicals are called inhibitors, because they inhibit reaction.Inhibitors that occupy the active site and prevent a substrate molecule from binding to the enzyme are said to be active site-directed (or competitive, as they 'compete' with the substrate for the active site).Inhibitors that attach to other parts of the enzyme molecule, perhaps distorting its shape, are said to be non-active site-directed (or non competitive).

Most enzymes operate with a very narrow range of temperatures. We tested the activity of Catechol oxidase at 4 different temperatures (celcius) 0, 23 (room temp.) 40, and 100. Water was our controlled substance which remained at zero for all three temperatures. The Avreage for 0 degrees celcius for all three...
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