Amylase is an enzyme that hydrolyzes starch into glucose as well as other small molecules, for example, maltose. Amylase is an enzyme in the glycoside family. It binds to peptidoglycan in cell membranes with a surface layer homology (SLH) domain.
The ability to break down starch into sugars is extremely useful in the food industry. Researchers have investigated the amylases of different species to make decisions about the synthesis of the amylase for industrial use. Both humans and bacteria make amylases that highly conserve a sequence of 511 amino acids that are believed to be extremely important for the structure and function of the enzyme. Scientists have confirmed that certain dipeptide and tripeptide sequences yield valuable information about the structure, function, and evolution of the enzyme. But how would you introduce this information to you students?
Following is one way to introduce your students to the similarities and differences in the amylases of people and bacteria.
A sample lecture about amylase
Begin by telling your students that here is some basic information about amylase they may already know.
Human amylase, also known as salivary amylase, is an enzyme that in people is mainly found in saliva. It breaks down the complex carbohydrates in your food into simple sugars.
Salivary amylase also acts as the substrate for the bacterial colonization of your teeth. Amylase binds to your teeth and provides an anchor for the bacteria in your mouth to grow on.
This means that there is a tradeoff between the benefits of amylase for digesting your food and its side effect of promoting the growth of bacteria that cause plaque and tartar as well as tooth decay. But amylase helps to release a small but measurable amount of glucose that enters your bloodstream even before you swallow your food, as well as a substantial amount of glucose when the bolus of your digested meal reaches your small intestine.
The amino acid sequence of human salivary amylase varies very little from person to person, although scientists have identified variations of amino acid sequences in human amylases found in the pancreases compared to those found in saliva. The amino acid sequences in bacterial amylases, however, may vary considerably.
That’s probably because bacteria have to function in many different oral environments. People who brush their teeth after every meal probably have a different bacterial amylase compared to people who never brush, and people who have accumulated tartar and plaque have bacterial amylase that isn’t identical to those who have cleanings at their dentist’s office every year.
Scientists have identified extreme differences in bacterial amylases studied for industrial use:
- There are amylases that operate optimally at pH levels ranging from 1.5 to 11.
- There are amylases that operate optimally at temperatures ranging from 25° C to 100° C.
- Molecular weight of α-amylases vary from 10 kiloDaltons to 210 kiloDaltons.
And even though there is relatively little variation in the structure and function of human amylases, humans can carry from two to 17 genes for encoding the production of amylases, affecting metabolic diseases like diabetes.
So, how can you give your students the hands-on laboratory experience to understand the differences between human salivary and bacterial amylases?
Teaching About Human and Bacterial Amylases in the Lab
You can use Modern Biology to give your students a lab experience measuring the differences in salivary and pancreatic amylases. In this experiment, students use gel filtration chromatography to measure the sizes of different proteins in a complex mixture.
Modern Biology provides all the test materials and reagents you need for this experiment, but you can use Modern Biology to take the topic farther. Your most enterprising students can research and develop a method of purifying amylase from saliva sample so they can run a test to see if salivary amylases from different people have different sizes. They can test for similarities and dissimilarities in amylases between normoglycemic and diabetic students. They can look for differences and similarities in amylases in siblings and non-related persons.
Modern Biology also offers EXP-301: The Length of DNA Molecules. In this experiment, your students refine their skills in doing electrophoresis to measure the lengths of standard and unknown DNA. This approach can also be applied to purified amylases. In EXP-304: Molecular Cloning, your students can develop further skills useful in the biotechnology industry in a two-part exercise in which they first introduce a gene for ampicillin resistance into E. coli, sterilize the product, and then amplify and isolate the plasmid without toxic materials.
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For forty years since Modern Biology Inc. was founded by Dr. John Anderson, and has followed the same fundamental pedagogical principles.
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