explain the relationship between enzyme structure and specificity? | Yahoo Answers
Multiple Choice Questions (MCQ) topic quiz Which property of an enzyme is responsible for this specificity? . 14 The action of an enzyme depends on the specific structure of its active site. Curve X represents the relationship between an enzyme and the concentration of its substrate under optimal conditions and. An enzymes structure is made up of proteins and the building blocks for these proteins are amino acids. When many amino acids join together. Quiz on Lecture Introduction to Enzymes The relationship between an enzyme and a reactant molecule can best be described as: a) a temporary association. b) an association stabilized by d) a permanent mutual alteration of structure.
If we imagine starting a camp-fire, which is essentially a chemical reaction between wood and oxygen, we could certainly speed the reaction up by dumping a huge bucket of gasoline on the fire. The gasoline makes the reaction go faster as indicated by the charred eyebrows and singed hair of anybody trying this at home but it also gets used up. In other words, gasoline on a fire is not a catalyst. One of the best everyday examples of a catalyst is the emissions control system in your car.
The main part of this system, unsurprisingly, is called a catalytic converter. This device is a container with a series of small screens coated in precious metals platinum, rhodium, etc. These metals are catalysts for the conversion of nitric oxide a nitrogen atom bonded to an oxygen atom into nitrogen and oxygen.
Easy Biology Class
Figure of a catalytic converter How do catalysts work? Most catalysts including enzymes work the same basic way, because most chemical reactions including biochemical ones work the same basic way.
As a good basic example, lets look at the nitric oxide reaction from the last section. What you have is the collision of two molecules of nitric oxide that results in the breakage of nitrogen-oxygen bonds and the creation of new nitrogen-nitrogen and oxygen-oxygen bonds. Figure showing two molecules of nitric oxide gas colliding to form a molecule of nitrogen gas and a molecule of oxygen gas If we were to dump a whole bunch of nitric oxide molecules into a normal jar with no catalytic converterand we were able to get an extreme close-up of what was going on at the molecular level, we would see millions of N-O molecules spinning and tumbling in space, smashing into each other and ricocheting off the walls of the jar at incredible speeds.
Very, very few nitrogen or oxygen molecules would be created, whereas most ofthe nitric oxide molecules would just bounce off of each other. Why the nitric oxide molecules bounce off each other: You also know that if you try and align one pole of a magnet with the same pole of the other, the magnets will repel.
Nitrogen and oxygen atoms are like magnets in this sense. Figure showing magnets attracting and repelling and a figure a nitrogen and oxygen atom attracting and repelling.
The first rule is that there is a mutual attraction between red magnets and blue magnets. This means that if you stick the north pole of a red magnet to the south pole of a blue magnet, they will stick together, just like you would expect with two magnets.
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.
Biochemistry Multiple Choice Quiz: 15
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.Function of Enzymes: Substrate, Active Site & Activation Energy
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. Here the enzyme is specific not only to substrate but also to its optical configuration. Optical specificity of enzyme is considered as the highest specificity shown by any class of enzyme in the living world.
L-amino acid oxidase acts only on L-amino acids, similarly D-amino acid oxidase acts only on D-amino acids. Another good example for optical or stereo specificity of enzyme is the action of amylases. Starch, glycogen and cellulose are the polymer of glucose molecules joined by glycosidic linkages.
Geometrical specificity In geometrical specificity, single enzyme can act on different substrates having similar molecular geometry and hence here specificity is very less. Alcohol dehydrogenase can oxidize both ethanol and methanol to yield corresponding aldehydes since both these alcohols have similar molecular geometry. Co-factor specificity Co-factors are non-protein part of enzyme required for the functioning of some enzymes. Enzyme which requires co-factors for their activity shows co-factor specificity.
Only correct combination of substrate and co-factor allows enzymatic reaction. In the absence of specific co-factor, the enzyme will be inactive even if there are plenty of substrates. Selectivity of enzyme to their substrate Different types: Bond specificity — specific to bonds 2.
Group specificity — specific to bonds and groups surrounding the bonds 3. Substrate specificity — specific to only one substrate and reaction 4. Stereo specificity — specific to substrate and its optical conformation 5.
Geometrical specificity — substrates having similar molecular geometry 6.