What is an enzyme and what it does

Inside the human body there are approximately 37.000.000.000.000.000.000.000 (millions of millions of millions) of biochemical reactions per second. If I have to wait about 5 minutes to boil water, how the hell does the body to carry out so many chemical reactions at once and so fast? The answer are the enzymes.

Sometimes when I write posts for this blog, I find myself not being able to explain something that is a little complex because I need to explain some basic concepts first. While I was doing my research about lectins, I had to first explain what the digestive system is and to explain that we need to know first what is an enzyme, so here we go!

To understand how enzymes work, we need to go over some basic chemistry. If you remember from school, a chemical reaction is just the process to convert something to something else. For example, in the following reaction A is converted into B.

Reactions can be carried out only if there is energy involved, they either need or generate energy to go from A to B depending on their nature.

Imagine you want to dissolve sugar in water, the easiest and fastest way is to dissolve it in hot water. You can try this at home, dissolve sugar in very cold water and hot water separately, you are going to see how one is faster than the other, obviously it is going to be faster with hot water. Hot water has more energy and that is what helps sugar to dissolve faster. Chemical reactions always go faster with heat.

What an enzyme could do in this case is to allow sugar to be dissolved in cold water as fast as it was hot water. Enzymes lower the amount of energy required to go from A to B and that is what speeds up the process, they are biological catalysts.

In the next image you can see a chart with energy in the y axis and the reaction progress in the x axis. As the reaction proceeds it needs more and more energy, once it reaches the peak of the curve the product of the reaction starts to be created, in our case B. What the catalyst does is to diminish that peak of energy required to go from A to B.

Almost all processes within the cell need enzyme, to this date there are 5000 types of reactions known. Although it is hard to believe an enzyme can shorten the duration of a reaction from a million of years to milliseconds, this is what fascinates me and amazes me about nature.

Some enzymes break big molecules into smaller pieces or on the contrary they can bind together smaller molecules to create a bigger one. This makes perfect sense because if you think about it, when we eat a piece of meat which is muscle tissue from an animal, then we convert it into tiny pieces to then reconvert it into our own muscles.

Enzymes do not modify the way a reaction is carried out. An enzyme is not going to modify the reaction’s direction or anything else, it just lowers the required energy and doing so, its velocity.

A few examples of enzyme that are present in some digestive processes are the following:

• Lactase
• Protease
• Lipase
• Amylase

It is easy to know the task these enzymes do by their names, since they are like the molecules they help to break and with break I mean digest.

Lactase for example is the enzyme to digest lactose and lactose intolerants are the ones who cannot produce lactase. It is believed that many years ago Europeans used to consume a lot of dairy and had a genetic mutation that allowed them to generate lactase for life, beyond their breastfeeding years. This is why the lactose intolerance rates are lower in Europeans and higher in Asians or Latin Americans.

Protease breaks down proteins into amino acids, lipase breaks down fats into fatty acids and amylase breaks down starches into glucose. If you want to know more about this, you can read this post: What is a nutrient?

There are many other interesting things about enzymes, for example, each enzyme is used in only one type of reaction, somehow enzymes know which are the participants in their reactions, otherwise there would be a chaos of enzymes reacting with whatever.

I let you and your curiosity to investigate more about enzymes. For now, I think I explained everything I need to move on to the digestive system.

I hope you liked this post, see you soon!