Research Paper on Enzymes

Introduction

Enzymes are proteins that act as catalysts within living cells. These catalysts are responsible for increasing the rate at which chemical reactions occur without their consumption. They are also known as substances that are produced by living organisms to act as catalysts for various biochemical reactions. They are responsible for accelerating chemical reactions. They act on substrates in their conversion into different molecules, known as products. Their structure is composed of one or more long chains of interconnected amino acids. The cells in the human body are chemical factories. Most of the substances are synthesized within the cells, which implies that hundreds of chemical reactions take place in the cells (Bettelheim, Brown, Campbell, and Farrell, 2015).

Lock and Key Hypothesis

Both substrates and enzymes are geometrically shaped to fit exactly into each other. Hence, this is their lock and key hypothesis due to their natural geometric shapes. Besides using this hypothesis, it does not explain the level of enzymes' stabilization, which is one of the problems of this hypothesis. Anytime a substrate enters an active enzyme site, the enzyme changes its shape slightly to match the substrate. Therefore, if enzymes are designed to fit a substrate, then there is no need to adjust their shape. Some scientists such as Daniel Koshland have also tried to modify the lock and key hypothesis by suggesting that enzymes are flexible and that is why their active sites are usually constantly reshaped by interaction with substrates (Jencks, 1987).

Induced-Fit Hypothesis

The induced-fit hypothesis mainly describes how enzymes work considering their active sites are not exactly complementary. It states that enzymes' active sites are not exactly complementary, and they change shape in the presence of a specific substrate to complementary. Anytime a substrate molecule collides with an enzyme, the shape of the active site adjusts itself so that the substrate will fit and an enzyme-substrate complex reforms (Roberts 1987). An enzyme's active site forms a complementary shape to the substrate after binding.

Factors Influencing Enzyme Activity

There are different factors that influence enzyme activity. For example, the concentration of substrates and an enzyme primarily impacts their activity. Other factors that influence enzyme activity include environmental conditions such as temperature, PH values, and the presence of inhibitors. The activity of enzymes is affected by temperature conditions as the rate of a chemical reaction increases with a rise in temperature up to a certain level. Inhibitors prevent enzyme functionality by affecting this activity in two different ways such as through some inhibitors known as competitive inhibitors which having the same structure as the substrate molecule (Csuros, 1999). Another way is when noncompetitive inhibitors try to react with the enzyme's active site changing its shape.

How pH Affects Enzyme Activity/Hypothesis

Changes in pH affect the enzyme in different ways such as its shape and also the charge properties of the substrate. It causes especially the substrate to form a substrate that cannot bind to the active site of the enzyme or either not undergoing catalysis. Enzymes have a pH optimum that is different for every enzyme. For example, high acidity increases the reaction with enzyme (Morton and Perry, 2012). Enzymes work differently in such a way that others work in acidic surroundings but the favorable pH value for other specific enzyme depends on the biological system.

References

Bettelheim, F.A., Brown, W.H., Campbell, M.K., and Farrell, S.O., 2015. Introduction to General, Organic and Biochemistry. Cengage Learning.

Csuros, M. and Csuros, C., 1999. Microbiological examination of water and wastewater. Boca Raton, Fla.:Lewis.https://books.google.co.ke/books?id=AtjDUn5KfG0C&pg=PA33&dq=Factors+Influencing+Enzyme+Activity&hl=en&sa=X&ved=0ahUKEwii9dGVvOHZAhXLFsAKHZsjAcMQ6AEIKzAB#v=onepage&q=Factors%20Influencing%20Enzyme%20Activity&f=falseJencks, W.P., 1987. Catalysis in chemistry and enzymology. New York: Dover Publ.

Morton, D., Perry, J.W., and Perry, J.B., 2012. Laboratory manual for human biology. Belmont, CA: Brooks/Cole.

ROBERTS, M.B.V., 1987. Biology: a functional approach. London: Thomas Nelson & Sons.