Enzymes - Nature's Magic

[Music] everybody loves a picnic but this isn't a story about picnics it's about something much more fundamental some very core of the Mystery of Life [Music] enzymes you've never seen an enzyme they're so small microscope yet they are so important that without them you wouldn't even exist if we were to take away all the enzymes in the world people wouldn't be able to digest food the complex processes of metabolism and energy conversion occurring in the millions of cells could not take place no human being could survive not just people no animal could live either without enzymes nothing would grow there would be no food no grass no trees the activity in every living cell would stop without enzymes our world would be as Barren as of the Moon what are these things we call enzymes what is the nature of their awesome power science is just beginning to explore these complex questions with the help of our laboratory assistant we'll explore them but first let's visit the most fundamental unit of life the cell cells are almost unbelievably small but they're among the most INF factories in the world hundreds of chemical reactions occur within a cell every minute complex compounds are built up others are broken down to do their work cells use hundreds of different enzymes an enzyme giant natural protein though it is produced by living cells it is not itself alive enzymes are composed of long chains of amino acids linked together by peptide bonds this is a model of an enzyme each colored strand on the model represents a acid chain this particular enzyme is composed of four chains and each chain is made up of 300 amino acid links the model indicates the positioning of the chains this is a different model of the same enzyme and shows the structure of each amino acid link the pink strand indicates the main flow of the chain corresponding to the green strand you saw in the first model what complicated structures these tiny enzymes are scientists are continually developing new methods to study them such as x-ray crystallography which diagrams the density of an enzyme and helps in the development and understanding of accurate scale models like this enzymes have the ability to change other compounds without being changed or altered themselves this action is called catalysis and it's the key to understanding how enzymes work each enzyme has what is called an active site an area of the enzyme that actively engages other compounds to cause a reaction this area is an active site because of its complex structure one type of enzyme will work with only one other type of compound a compound whose structure complements its own in other words enzymes are specific fitting together with another compound like two pieces of a puzzle our assistant can demonstrate how it works let's take a puzzle piece and pretend it's an enzyme this area is its active site which must come into contact with a complimentary compound when a molecule comes along with a shape that doesn't fit nothing happens they simply ignore each other but when the enzyme Finds Its complimentary compound they fit together perfectly then a reaction takes place in this case the enzymes splits one compound into two different compounds the enzyme itself doesn't change it's free to do the same job again and again with other compounds the enzyme is acting as a catalyst by promoting a reaction this is a very efficient way to work but enzymes aren't just efficient they're fast too in fact a single enzyme may change more than a 100,000 compounds in 1 second but enzymes don't just divide compounds they do many different jobs if we pretend our puzzle piece is a different enzyme it might find two separate compounds and join them to form a single new compound almost every chemical reaction in living organisms is controlled by enzymes for example before food can be absorbed by our bodies and used as fuel it must be broken down and converted to small [Music] molecules this diagram can help us see what happens when we eat a hamburger take a bite chewing is the first step in the process of breaking food into small particles chewing also releases saliva which mixes with the food saliva contains the enzyme amales which begins to break down the starch in the hamburger bun into smaller molecules swallow the food partially broken down by chewing and by the enzyme passes through the elementary canal and into the stomach here stomach cells secrete a gastric juice that contains another enzyme pepsin pepsin helps break down protein in the meat it's sort of a double pronged attack amalay for the carbohydrates pepsin for the proteins now the hamburger is a soup-like mixture and passes into the small intestine where a pancreatic juice is released this juice contains a whole range of enzymes each one specially suited to break down a particular type of nutrient the hamburger is now reduced to a group of small all molecules like amino acids simple sugars and fatty acids as well as the vitamins salts and water that were in the hamburger from the start these molecules are now ready to be absorbed by the small intestine and at last used by the body important thing to remember about this whole process is that none of it not a single step could have taken place without enzymes in the world of plants flowers like the rose are beautiful but it is the green leaves of living plants that perform a miracle essential to all our lives photosynthesis energy from the Sun carbon dioxide from the air and water are absorbed by the living cells of plants and converted into sugars the entire world of living things both animal and vegetable depends on this process for food scientists don't completely understand how photosynthesis works but they do know it couldn't occur without enzymes practically everybody likes cheese different cheeses are aend diet all around the world the basis for all cheese making is milk and an enzyme called renin renin coagulates part of the milk into curds the basic substance of cheese it's simple to do take a container of milk add a little renin mix them together and and heat them in a short time the enzyme separates the milk into curds and whey primitive man discovered how to make cheese long before he had any idea what enzymes were several thousand years ago the stomachs of slaughtered animals were used as canteens for carrying milk and water when people left their milk canteens out in the hot sun for a few hours they noticed that the milk would clot into soft creamy lumps that had a sharp strangely Pleasant taste primitive man didn't know why but we know that the enzyme renin found in the lining of the animal's stomach was changing the milk into cheese today we found a way to produce Rena in the mass production of cheese Nature has in fact provided an enzyme for just about every job when the enzymes in yeast change the sugar and grapes to alcohol you have wine when enzymes convert grains into sugar then into alcohol you have beer today scientists have developed many other ways for enzymes to serve man doctors have long recognized the value of enzymes in identifying and monitoring liver diseases diabetes and infections of the pancreas and enzyme injections can be used to dissolve blood clots and to help reduce the possibility of heart and brain damage this strip is coated with an enzyme the enzyme will change color and measure the amount of sugar in the solution doctors use this strip to test urine samples for evidence of diabetes in patients enzymes can help mankind ins still other ways we have become increasingly aware that we must protect and preserve our environment this means reducing pollution and that's where enzymes come in again enzymes promise to play an increasingly important part in our fight against pollution since they have two characteristics that are especially valuable first they are specific like an arrow they go straight to their target and to one Target only one enzyme acts on only one compound this means it leaves other compounds undisturbed the second valuable characteristic of enzymes is that they are completely natural substances produced by living cells and they are not pollutants themselves in fact enzymes are now replacing dangerous acids in chemicals in a number of industrial processes like tanning animal hides and removing protein waste from dairy and fish processing Machinery thus enzymes effectively reduce the number of pollutants being added to the environment still other wonders lie in the future there are some 2 billion people in the world who don't have enough protein in their daily diet scientists believe enzymes can provide protein by helping to process protein Rich vegetables soybeans are a good example they have a high protein content they're easy and cheap to grow there's just one thing wrong with them they taste terrible but enzymes can be used to remove both the bad taste and the parts of soybeans that are hard to digest what's left is raw vegetable protein that can be made into a meat-like substance that's not only attractive but taste good too so enzymes May ultimately help us surmount perhaps the greatest problem our world has ever faced the awesome challenge of feeding too many people with too little food it's a big job but enzymes have been doing big jobs for a long time until just recently they were doing it with no help from man now things are a bit different through his knowledge of enzymes man has gained a great understanding of the forces that shape his world and new tools with which to forge his future [Music]