Have you ever wondered how the food you eat gets broken down into the smallest molecules? Well, that happens because of the enzymes in your bodies. But what are these enzymes, how do they function, and what do they look like? All these questions and more are studied in Enzymology. Let's look at the first question. An enzyme is a biological molecule that acts as a catalyst, meaning that it speeds up certain chemical reactions, but doesn’t get broken down or used up in the process. Without enzymes,the chemical reactions in our body would be too slow for us to remain alive ! So let's take a deeper look into enzymology.
Enzymes are actually protein molecules, meaning they are giant structures made of carbon, oxygen and hydrogen, but also a little bit of nitrogen. These structures are a type of biological molecule known as a polymer, extremely long chains formed from a repetition of a specific molecular unit. These are made up of atoms covalently bonded. This long chain twists and turns to form a complex shape, and contains a pocket known as an active site where larger biological molecules attach and are broken down. These active sites have shapes that exactly fit a certain type of molecule, and no others, so each enzyme in our body can catalyze only one type of chemical reaction. Did you know there are approximately 3,000 enzymes that exist in our human body, each of them with a specific function? However, after a certain temperature, the energy in the atoms of the protein molecule becomes very high, causing the enzymes to change shape. The shape of the active site is disrupted too. We say that the enzyme is denatured. Cold temperatures also stop an enzyme from functioning properly, by slowing down its catalyzation.
The pH of the enzyme’s surrounding solution also affects its functioning. The amino acids in many enzymes have slight charges. The attraction between positive and negatively charged amino acids plays a role in determining the enzyme shape, as it affects the folding of the molecule. Changing the pH level will affect the charges on the amino acids, and thus, means that the shape of the active site can be altered.
Let’s look at an example of an enzyme in the human body. Lipase is an enzyme that breaks down lipids, essentially fats. Normally, the fat molecule requires a certain amount of energy, known as the activation energy, to break the bonds within it and allow it to decompose into fatty acids and glycerol. However, when a lipid molecule binds to the active site of lipase, the lipase provides an alternate path for the reaction with a lower activation energy. This means that the lower energy limit is more likely to be met, and is met much quicker, substantially quickening the process.
It is not surprising that enzymes are critical for every aspect of cellular life. Every day, trillions of chemical reactions occur in our body to facilitate essential metabolic processes and this is where enzymes come into the picture. It’s unbelievable how these enzymes play a big part in shaping our lives !
Until next time !
By : Malaya Parwani and Pulkit Sureka
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