The Nature of Proteins
Proteins consist of carbon, hydrogen, oxygen and also nitrogen.
Proteins are macromolecules. They are constructed from one or more
unbranched chains of amino acids; that is, they are polymers (
Compound whose molecule consists of many repeated units linked
together). A typical protein contains 200-300 amino acids but some are
much smaller (the smallest are often called peptides) and some much
larger.
Amino Acids
Amino acids are the building blocks (monomers) of proteins. 20
different amino acids are used to synthesize proteins. The shape and
other properties of each protein is dictated by the precise sequence
of amino acids in it.
Each amino acid consists of an alpha carbon atom to which is attached
a hydrogen atom
an amino group (hence "amino" acid)
A carboxyl group (-COOH). This gives up a proton and is thus an acid
(hence amino "acid") [IMAGE]
One of 20 different "R" groups. It is the structure of the R group
that determines which of the 20 it is and its special properties. The
amino acid shown here is Alkaline.
Amino acids contain an amino or NH2 group and a carboxyl (acid) or
COOH group.
The ionization of water
Amino-acids at physiological pH values predominate at an ionization
state where the alpha-amino group is positively charged (a cation)
whereas the carboxyl group has a negative charge (an anion). This is
called a zwitterion.
The Peptide Bond
The amino acids are linked linearly through peptide bonds. These bonds
are formed via a dehydration synthesis reaction between the carboxy
group of the first amino acid with the amino group of the second amino
acid. Water is given of in this reaction therefore it makes it a
condensation reaction.
If you would wish to reverse this reaction you would use a hydrolysis
reaction. To do this you would add water.
[IMAGE]This is an example of a condensation reaction which results in
the formation of peptide bonds.
When two amino acids are combined this forms a dipeptide.
[IMAGE] In this experiment, the enzyme rennin will be used. Rennin is a coagulating enzyme occurring in the gastric juice of the calf, forming the active principal of rennet and able to curdle
In the subsequent essay I will discuss and explain the relative function of the Prion protein. The Prion protein, also known as PrPC, ‘’is a membrane-anchored protein with two N-glycosylation sites and, although it is highly expressed in the nervous tissues, its physiological functions have yet to be well established’’ (Coordination Chemistry Reviews). PrPC/PrP is found in healthy brains in this form, and consists of 250 Amino Acids, yet after a simple misfolding in the secondary structure; this can alienate the PrP and forms PrPsc, which is the abnormal form of the Prion protein. The infectious agent PrPsc causes neuropathological changes in the brain, and instantly places the individual under the category of someone with the prion disease. PrPsc forms insoluble fibres and thus cannot be studied well using Nuclear Mass Resonance (NMR), and it is also more resistant to protease digestion. Furthermore, ‘’ The transmissible spongiform encephalopathies (TSEs) arise from conversion of the membrane-bound prion protein from PrPC to PrPSc, the latter being the scrapie form. Examples of the TSEs include mad cow disease, chronic wasting disease in deer and elk, scrapie in goats and sheep, and kuru and Creutzfeldt-Jakob disease in humans’’ (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904554/. 2014). The following diagram shows the conversion from PrPc to PrPsc:
Proteins are one of the main building blocks of the body. They are required for the structure, function, and regulation of the body’s tissues and organs. Even smaller units create proteins; these are called amino acids. There are twenty different types of amino acids, and all twenty are configured in many different chains and sequences, producing differing protein structures and functions. An enzyme is a specialized protein that participates in chemical reactions where they serve as catalysts to speed up said reactions, or reduce the energy of activation, noted as Ea (Mader & Windelspecht).
Abstract/Summary: “Proteins account for more than 50% of the dry weight of most cells, and they are instrumental in almost everything organisms do” (Campbell, 1999). The significance of proteins to the continuation of our biological systems is undeniable, and a study of how to quantify proteins seems an appropriate introduction to our studies of biology. In order to study proteins we must first know how to separate then quantify the amount using basic principles of experimental design such as a standard curve. In this experiment we wish to quantify the amount of previously extracted protein by measuring the absorbance of the unknown amount and determining its concentration by overlaying it against a standard curve of the absorbance of known concentrations of the protein. We used the dye agent Bradford Protein Assay to get an absorbance of 0.078, 0.143, 0.393, 0.473, and 0.527 at the protein’s respective concentrations of 0.28, 0.56, 0.84, 1.12, and 1.40 mg/mL. When a best-fit line was applied to the standard curve, and the absorbance of our unknown concentration (0.317 A) plotted, we estimated a concentration of around 0.84 mg/mL of protein. Our calculations indicated a quantity of 168 mg of protein, which was an approximately 8.96% yield of the projected 1875 mg that was expected. Errors that may have led to this small yield percentage may have stemmed from our previous lab and our initial attempts to extract the desired amount of protein.
The Structure and Function of Carbohydrates Large biological molecules are called macromolecules, there are giant molecules (polymers) made up of repeating units (monomers). Carbohydrates are one of the main classes of biological molecules. Macromolecule units (monomers) are joined together by condensation reactions and hydrolysis reactions split macromolecules down into their individual units. Carbohydrates are molecules that contain elements of carbon, hydrogen, and oxygen. Carbohydrates have a 2:1 hydrogen to oxygen ratio, there are twice as many hydrogen atoms as oxygen atoms (the same proportion as in water).
of titrant used. In the case of amino acids, the titrant will be both an acid
Protein have connection with amino acid to help in functions of: skin, muscle, hair and bones
n.d. - n.d. Peptides and Proteins. Proteins. Retrieved July 25, 2008, from http://www.cd http://www.cem.msu.edu/reusch/VirtualText/protein2.htm Ophardt, C. E. (2003).
In total, there are around 20 amino acids that the human body uses to build proteins.
Each protein is a large complex molecule; these molecules are made up of. of a string of amino acids. There are 20 different amino acids that occur naturally to form proteins and they all have the same basic structure. The. The 20 amino acids the body needs can be linked in.
Moderation is vital in all aspects of life and is necessary for overall health, including with one’s food intake. Protein is one of the many important nutrient building blocks that is necessary for proper growth and good health. However, eating excessive amounts of any nutrient or inadequate amounts, can cause various health concerns. Scientists have been able to estimate the amount of nutrients that the body requires. However, the amount of any particular nutrient varies from person to person, depending on your “age, sex, general health status, physical activity level, and use of medications and drugs” (Schiff 2013). It is also important to remember that consuming the required amount of nutrients that meets your dietary guidelines does not
An alpha amino acid is made up of a central carbon atom, or the alpha carbon, which is linked to an amino group, a carboxylic acid group, a hydrogen atom, and a distinct R group, called the side chain. There are twenty different kinds of side chains that vary in shape, hydrogen-bonding capacity, chemical reactivity, charge, size, and hydrophobic character that are typically found in proteins. All proteins in all species are made up of the same set of twenty amino acids, with a few exceptions. In order to classify amino acids, the molecules are assorted in four groups on the basis of the general characteristics of their R groups. The four groups are hydrophobic amino acids with nonpolar R groups, polar amino acids with neutral R groups but the charge is not evenly distributed, positively charged amino acids with R groups that have a positive charge at physiological pH, and lastly, negatively charged amino acids with R groups that have a negative charge at physiological pH. The simplest amino acid is glycine because it has only a single hydrogen atom as its side chain. Alanine is the next simplest amino acid because it has a methyl group as its side chain. Seven of the twenty amino acids have side chains that are readily ionizable and they are able to accept or donate protons to facilitate reactions and form ionic bonds. Amino acids are typically abbreviated to a three-letter, which are typically the first three letters
"Within a single subunit [polypeptide chain], contiguous portions of the polypeptide chain frequently fold into compact, local semi-independent units called domains." - Richardson, 1981
Proteins (macronutrient), which are found in animal products, nuts and beans, they help to build new cells, maintain tissue and synthesis new proteins essential for performing basic bodily functions. Proteins are in abundance in the human body and are present in the outer and inner membranes of all living cells (Dummies, 2018). Proteins are essential for building new cells, maintaining tissue and helping new proteins needed for basic bodily function (
Enzymes are one source of proteins in our body. They speed up chemical reactions such as the digestion of carbohydrates and the synthesis of cholesterol in the liver. Enzymes increases the rate of the chemical reactions. Hormones found in our body is also a protein. Hormones are chemicals that are created in one part of the body and carry a messages to another organ. For example, glucagon and insulin are both hormones. They are made in the pancreas and travel throughout the body to regulate blood glucose. Fluid is present in most of the compartments of your body. Its within the cell, blood, and much more spaces. It's the minerals and protein that keep them balanced. Proteins are macronutrients that are too large to pass across the membrane, but since it attracts water they maintain proper fluid balance. Allowing your brain to go without glucose in times of starvation or low carbohydrate, the body will sacrifice proteins from your muscles/tissues in order to make new glucose from amino acids in a process called gluconeogenesis. Protein gives the structure to bones, teeth, and