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Enzyme
From CreationWiki, the encyclopedia of creation science
An enzyme is an protein that serves as a biochemical catalyst, encouraging chemical reactions, usually speeding them up. Organisms could not function if they had no enzymes.
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Structure
Enzymes are composed of a globular protein chain, which is neatly and orderly situated, allowing only several specific amino acids to be bonded. It ranges in size from just 62 amino acids to over 2500 amino acids. The enzyme employs a three dimensional shape which is constructed of several polypeptide chains being neatly twisted and folded to produce its unique figure. This shape is relatively larger than the substrates that bind and act with it. Only a small portion of the enzyme comes into contact with the substrates and co enzymes that it catalyzes. It has specialized mechanisms which regulate the activity of the enzyme in response to changes in temperature and can provide feedback regulation for which substrate or co enzyme it is catalyzing.[1]
The enzyme has a high level of specificity which can be described by the Lock and Key Hypothesis. This was first introduced into the scientific world by Emil Fischer, a German Chemist, in 1894. His hypothesis states that there is only one specific enzyme that can bond with one specific substrate. This means that only one enzyme will cause one specific reaction. The way this works is the enzyme is in a certain shape. This shape will allow only one single specific substrate to mate up with the design and form a bond. The area where the substrate matches the enzyme is called the active site. The whole job of the enzyme is to perform a catalytic role. The enzyme speeds up the reaction of a substrate, causing the product to be formed. When the enzyme has completed this reaction, the substrate falls off in several different pieces as a product of the reaction. The enzyme itself, however, remains intact and waits for another substrate to bind with it to cause another reaction. The enzyme can carry on like this for a long period of time. The enzyme does not go out in “search” for a substrate; it basically waits for a substrate to collide with it before it can bond. Thus, the higher concentration of substrates, the more bonds will be made. This process can become tedious as only one specific substrate must bond with one specific enzyme. The substrate must collide with the enzyme with a relatively high amount of force. The substrate must also be positioned in a specific manner that allows for it to fit right into the enzyme.[2]
Function
The enzyme is a highly specialized, biological protein, created in a cell. Their most important function in the body is to serve as a catalyst for chemical reactions; however they are mandatory in several other cellular functions. They are required for any muscle to contract, any cell to transport its contents, and for most forms of active transport. They are also important for many viruses to release their infections. Enzymes are required for the replication of DNA, and blood coagulation. Enzymes are absolutely mandatory for any higher form of life to carry on its daily functions in an uneventful manner.
Enzymes are very important in the process of digestion. Digestive enzymes starts as soon as one begins to chew his food. The enzyme amylase begins breaking down carbohydrates into simpler forms at this stage. Next, the food enters the stomach. It then is met with pepsin and protease. The enzymes begin digesting the food and breaking them down into simpler components with the ultimate goal of having each molecule broken down into its simplest form so that absorption can occur in the small intestine. The small intestine also does release several different enzymes during this process. The small intestine is where the vast majority of digestion occurs so it is fitting for the pancreas and small intestine to release enzymes here.
The enzyme is also responsible for creating energy carries, such as Adenosine triphosphate (ATP). This happens when a specific ATP Synthase enzyme bonds with a high energy molecule, containing one phosphate group, is coupled with an ADP molecule containing two phosphate groups. The enzyme catalyzes the reaction and soon the structures separate. The body is then left with an enzyme, a low energy molecule, and an ATP molecule. Most of this process occurs inside of the mitochondria, and the body uses the energy as soon as it is called upon.[3]
Another extremely important aspect of the enzyme’s biological function is its role in DNA replication. This happens with a group of enzymes know as DNA polymerase. It basically extends the current DNA strand. It can not create a new strand. After a small strand of DNA binds with a template strand; can the DNA polymerase synthesis DNA. The small fragment of DNA that binds with the template strand is called the primer. The primer attracts RNA nucleotides to bind with the DNA nucleotides. Then, the polymerase reads the template and grows the chain by continuously adding more nucleotides. Finally, the polymerase initiates the end of replication, and the separate strands are then checked over to ensure they are free of errors. This point in the process is known as termination. [4]
Reaction rate factors
Temperature
The temperature in the enzymes vicinity can also play a crucial role in its activity. Generally, there is a specific range of temperature which is acceptable to a certain enzyme. The temperature directly affects the enzymes reaction rate. This is called the temperature optimum of the enzyme. For example, a shrimp that lives deep in the cold waters of Alaska will have enzymes that work optimally at a temperature of 4* C. Likewise, a bacteria that lives in the hot springs of Yellowstone National Park would have a temperature optimum of 95* C. It should be noted that as the temperature grows warmer, the acceptable range for a temperature optimum also increases. So instead of having an optimum range of 4*-6* C, it swells to 25*-35*C, and so on. Also, as the temperature increases, the range of the enzyme’s optimum temperature also increases. This is true until about 40*C. The enzymes in the human body peak in their acceptable range of optimum temperature anywhere from 32* C- 40* C. This range is extremely broad in comparison to the range at higher or lower temperatures. As the temperature raises, the enzymes range of optimum temperature begins to decline, until eventually it is a very narrow rage.[5]
The enzymes in the human body work best at around 35.7*C. If one views a graph that indicates the optimal range for an enzyme one will notice that this range is considerably broader around these temperatures. One could conclude from this that God designed the body in such a way that virtually no matter what temperature the human body is at, all of its enzymes are still working at an optimum rate. This is a fascinating feature that the body has been designed with and should be a testament to how intricate and specialized the human body has been formed by the Creator.
Substrate concentration
Inhibitors
 Crystallographic structure of influenza A N9 neuraminidase and its complex with the inhibitor 2-deoxy 2,3-dehydro-N-acetyl neuraminic acid. |
 Diagram of competitive enzyme inhibition. (a) Normal reaction, (b) Inhibition. S: substrate; E: enzyme; I: inhibitor; A: active site. (1) Enzyme binds substrate; (2) Enzyme releases products; (3) Enzyme binds inhibitor; (4) Inhibitor competes with substrate. |
References
- Energy and Enzymes Clinton Community College, November 12, 2008.
- Structure and Function of an Enzyme Unknown Author, Microsoft, March 26, 2009.
- Effect of temperature on enzyme activity Brooklyn College, November 27, 1997.
- Enzymes- mode of action Unknown Author, Biotopics, March 22, 2009
- Enzymes and Digestion Karen, Enzyme stuff, August 25, 2005
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