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FSE1105-Thanatochemistry-Chapter12.pptxProteins and Enzymes
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(C) 2017 - Professor Joseph Finocchiaro
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Proteins
The Greek word “proteios” means “of first importance”.
Protein compounds are fundamental building blocks of many of the body’s structures such as nervous tissue, muscles, cartilage, tendons, and ligaments.
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(C) 2017 - Professor Joseph Finocchiaro
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Proteins
Protein compounds can be formed in plant life by the addition of nitrogen from the soil to the carbohydrate compounds which were formed by photosynthesis.
Protein molecules are relatively large and complex structures containing many elements and atoms.
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(C) 2017 - Professor Joseph Finocchiaro
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Proteins
The words protein and amino acid become synonymous terms once it is understood how they are related.
A protein is actually a chain of amino acid molecules linked together by a chemical phenomenon known as a peptide bond.
The essence of a peptide bond is the alternating pattern of two hydrogen atoms and one oxygen atom on the external bonds of a protein molecule.
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(C) 2017 - Professor Joseph Finocchiaro
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Proteins
The smallest identifiable protein molecule is a single amino acid molecule called glycine.
Glycine consists of a molecule of methyl amine joined chemically to a molecule of carboxylic acid.
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Properties of Proteins
Proteins are in a liquid state at body temperature.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Protein is naturally hygroscopic and utilizes imbibation to maintain its liquid state.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Due to its hygroscopic nature, proteins are considered to be the body’s natural humectant and are essential in maintaining proper body moisture levels.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Proteins are amphoteric, consisting of both acid and base parts. Because it is amphoteric, this aids in the retention of moisture by the body even in excessive heat such as fevers or hot weather.
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Properties of Proteins
When the peptide bonds of a protein molecule are removed, water is shed by the molecule. The viscosity of the molecule increases as the water is shed. When all of the water is removed a solid particulate called a coagulate remains.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Coagulated protein is resistant to decomposition by hydrolysis.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Formaldehyde can also remove the peptide bonds from a protein molecule.
This is the chemical explanation for the drying out of body tissues which are exposed to formalin solutions.
The stronger the concentration of the formaldehyde, the more moisture extracted and hence the more firm the body tissue.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Protein molecules can undergo decomposition by the presence of water which causes a process called Hydrolysis.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Decomposition of a protein can occur or in two ways:
Deamination/Deaminization: the removal of the amine from an amino acid by another substance.
Decarboxylation: the removal of the carboxylic acid from an amino acid by another substance.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Complex proteins can undergo partial decomposition. Partial decomposition results in the separation of the single protein molecule into the specific number of amino acid molecules of which it was composed and held together by peptide bonds.
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(C) 2017 - Professor Joseph Finocchiaro
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Properties of Proteins
Complex proteins and amino acids can also undergo complete decomposition. This results in the creation of carbon dioxide, water, and urea from the protein or amino acid molecule. Some energy is also released by complete decomposition.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
An organic enzyme is a compound which normally acts as a catalyst for some type of chemical reaction such as hydrolysis.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
A catalyst will alter the rate of speed of the chemical reaction into which it is introduced but will not become part of the products of the reaction nor will it be altered by the chemical reaction.
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Organic Enzymes
Enzymes are said to be substrate specific.
A specific enzyme will only act upon certain substances or substrates.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
As an example:
If an enzyme is categorized as a member of the protease family it will only act on protein substances. It will not act upon carbohydrates or lipids.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
Enzymes possess physical and chemical properties similar to that of proteins.
One significant difference can differentiate proteins from enzymes:
Proteins are crystalloidal in nature and are therefore capable of passing through semipermeable membranes.
Enzymes are colloidal in nature and incapable of passing through semipermeable membranes.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
The names of many enzymes end in the suffix “-ase”.
Besides being substrate specific, enzymes can also be temperature and pH specific.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
Enzymes are known to be labile: they have the capability of regrouping and returning to original strength after working on a substrate over a period of time.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
Because of this labile property, enzymes do not cease to act upon the death of the organism which created them. If there is no more substrate to act upon at the time of somatic death the enzyme will act upon the very tissues which created it.
This is known as autolysis.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
Even the enzymes like lysozyme within each body cell will remain active after cellular death. It is essential that the exoenzymes and endoenzymes be neutralized after death to minimize the damage caused by autolysis.
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(C) 2017 - Professor Joseph Finocchiaro
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Organic Enzymes
The cavities of the torso are injected with a formaldehyde-based fluid (cavity fluid) to neutralize the exoenzymes of the digestive system. Arterial fluid acts upon the enzymes in the cells.
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(C) 2017 - Professor Joseph Finocchiaro
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(C) 2017 - Professor Joseph Finocchiaro
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References:
The following Textbook References were used to create this presentation:
Funeral Service Chemistry by Professional Trade Schools
Embalming: Theory, History, and Practice by Robert G. Mayer (5th Edition).
Charts were taken from the textbook unless otherwise indicated
Pictures and art used in this presentation have the reference and location stored in the graphic. Please hover the mouse over the image to find where it was obtained.
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