Enzyme structure and function - Wikiversity
The folding of a protein allows for interactions between amino acids that may be distant In enzymes, some of these amino acids form a site in the structure that. Read and learn for free about the following article: Enzyme structure and function . Consider a chemical reaction where a molecule A bonds with a molecule B to create a molecule A-B (A stuck to B). If gasoline isn't a catalyst, what is?. Organisms exchange matter with the environment and each other to grow and .. Describe the relationship between the structure and function of enzymes.
The membrane-spanning regions of membrane proteins are typically alpha helices, made of hydrophobic amino acids. These hydrophobic regions interact favorably with the hydrophobic lipids in the membrane, forming stable membrane structures.
Hemoglobin is a soluble protein - found in the cytoplasm of red blood cells as single molecules - which bind oxygen and carry it to the tissues.
In sickle cell anemia, a mutation in the beta-globin protein of the red blood cell increases its hydrophobicity and causes the mutant protein molecules to stick to each other, avoiding the aqueous environment. Chains of hemoglobin change the shape of the red blood cell from round to a sickle shape, which causes the cells to collect in narrow blood vessels. Active site The folding of a protein allows for interactions between amino acids that may be distant from each other in the primary sequence of the protein.
Rediscovering Biology - Online Textbook: Unit 2 Proteins & Proteomics
In enzymes, some of these amino acids form a site in the structure that catalyzes the enzymatic reaction. This site, called the active site of the enzyme, has amino acids that bind specifically to the substrate molecule, also called a ligand Fig.
In a similar manner, certain sites in cell receptor proteins bind to specific ligand molecules that the receptor recognizes. Alterations in amino acids that may be distant from each other in the primary sequence can lead to changes in folding.
The second rule is that there is a stronger mutual attraction between magnets of the same color: What this means is that a red magnet will prefer to stick to another red magnet, and a blue magnet will prefer to stick to another blue magnet, if given the choice.
So those are the rules about how our magnets behave. If the poles of the colliding magnets are lined up in the correct way, so that the north pole of one red magnet is contacting the south pole of the other red magnet, with the same happening for the blue magnets, what would happen?
But only if the alignment is correct! Figure of nitrogen and oxygen atoms colliding then bonding. This magnet thought experiment is a good approximation of what happens with real-life molecules like nitric oxide. But the alignment is key--nothing will happen without it.
This is where catalysts come in. They help with alignment. The odds favor nothing happening. This is what happens with nitric oxide molecules in a jar, when no catalyst is present. Figure of nitric oxide molecules in a jar unable to correctly align. But now imagine that we add an extremely motivated and conscientious magic gnome to the inside of our jar, with the instructions that he is to grab a red-blue in each one of his hands, align them in the right way, and then smash them together.
Adding this helpful gnome assistant will increase the rate at which red-reds and blue-blues are made, because achieving the right alignment is no longer a matter of random chance.
Figure of nitric oxide molecules in a jar correctly aligning in the presence of a catalyst. Catalysts are the real-life versions of our imaginary magic gnomes.
A platinum screen sits inside a catalytic converter attracting nitric oxide molecules to it and aligning them in just the right way, so that when they collide, the N and O switch places, and nitrogen gas and oxygen gas are created.
Catalysts make reactions fast by aligning reactants so that successful reactions are more likely! Enzymes are biological catalysts Enzymes are the catalysts involved in biological chemical reactions. Why enzymes are so important The big reason enzymes are important to life is because cellular energy is a precious resource. This increase in the total number of collisions per second would increase, just as a matter of probability, the number of correctly aligned collisions too.
So, in the end, shaking the jar harder much harder, perhaps would result in an increase in the speed of red-red and blue-blue production too, just like adding a gnome and keeping the shaking of the jar the same.
Figure of nitric oxide molecules in a shaking jar correctly and incorrectly aligning. By just shaking the jar harder, you choose to do the work yourself and forego the services of the gnome.
You get the same end-result, but it requires more energy expenditure on your part. If you use the gnome, you get to save this energy for other purposes: Or what if you have lots of energy available, but you have to do a lot of work to obtain it? Or, maybe you have extra energy, but you want to spend it on doing other important things. In any of these three cases, the added savings you get from using the gnome to do the work might make a world of difference. Pretty cool for a few minutes effort!
Consider a rabbit in a field. This rabbit has millions and millions of cells, all of which have billions and billions of chemical reactions going on, every second of every day that the rabbit is alive. The grass gets converted to simple sugars.
The simple sugars get converted to fuel molecules.
Enzyme structure and function
Burning fuel molecules releases energy, and this energy increases the speed with which molecules travel inside cells. A cell burning energy has the same effect on the molecules inside it as shaking our imaginary jar has on the red and blue magnets inside it. In both cases, work is being done that results in more collisions happening, which in turn results in more reactions happening. With the help of enzymes, this amount of energy is just enough not too much, and not too little to get molecules moving fast enough to react in the ways that the rabbit needs in order to go on living.
The energy released from burning the fuel molecules drives the molecules around at a certain speed, and the enzymes make sure that the molecules are aligned in just the right way so that the right kinds of collisions happen.
The molecules would be moving around with the same speed, but the collisions would be totally random: This is a huge problem for the rabbit, because most of what it does depends on the speed of the chemical reactions in its cells.