Biochemical Analysis of Snail Secretions

About the Enzymes (Enzyme Proteins) in the Snail Substance.

Globular or “spheroproteins” as those in the snail mucous are highly soluble in aqueous solutions. They act as enzymes and signal transduction proteins . Nearly all enzymes with major metabolic functions are globular in shape, as well as many signal transduction proteins.

Metabolism is the biochemical modification of chemical compounds in living organisms and cells. This includes the biosynthesis of complex organic molecules (anabolism) and their breakdown (catabolism). Metabolism usually consists of sequences of enzymatic steps, also called metabolic pathways.

Cell metabolism is the process (or really the sum of many ongoing individual processes) by which living cells process nutrient molecules and maintain a living state. Metabolism has two distinct divisions: anabolism, in which a cell uses energy and reducing power to construct complex molecules and perform other life functions such a creating cellular structure; and catabolism, in which a cell breaks down complex molecules and uses energy and reducing power to construct complex molecules and perform other biological functions. Cell metabolism involves extremely complex sequences of controlled chemical reactions called metabolic pathways.

Protein catabolism is the breakdown of proteins into amino acids and simple derivative compounds, for transport into the cell through the plasma membrane and ultimately for the polymerisation into new proteins via the use of ribonucleic acids (RNA) and ribosomes.

Through the metabolic processes enzymes (all enzymes are proteins) are capable of quickly reducing the swelling or edema of traumatized or injured tissues by actually "digesting" or breaking down damaged tissues and ruptured cells at the site of injury, allowing these waste materials to be removed quickly from skin lesions so as to reduce inflammation and subsequent pain, speeding the healing process and encouraging regeneration of tissue to then take place more quickly.

Enzymes act as signal transduction or messengers that regulate biological processes

In biology, signal transduction is any process by which a cell converts one kind of signal or stimulus into another. Processes referred to as signal transduction often involve a sequence of biochemical reactions inside the cell, which are carried out by enzymes and linked through second messengers. Such processes take place in as little time as a millisecond or as long as a few seconds.

In many transduction processes, an increasing number of enzymes and other molecules become engaged in the events that proceed from the initial stimulus. In such cases the chain of steps is referred to as a "signaling cascade" or a "second messenger pathway" and often results in a small stimulus eliciting a large response.

Unlike fibrous proteins (collagen, elastin) which only play a structural function, globular proteins can act as:

•  Enzymes, by catalyzing organic reactions taking place in the organism in mild conditions and with a great specificity.

•  Messengers, by transmitting messages to regulate biological processes. This function is done by hormones, i.e. insulin etc.

•  Transporters of other molecules throughout membranes.

•  Stocks of amino acids.

About Enzymes

All enzymes are proteins. An enzyme is a substance that acts as a catalyst in living organisms, regulating the rate at which life's chemical reactions proceed without being altered in the process. Enzymes reduce the activation energy needed to start these reactions; without them, most such reactions would not take place at a useful rate.

Like all catalysts, enzymes accelerate the rates of reactions while experiencing no permanent chemical modification as a result of their participation. Because enzymes are not consumed, only tiny amounts of them are needed. Enzymes can accelerate, often by several orders of magnitude, reactions that under the mild conditions of cellular concentrations, temperature, pH, and pressure would proceed imperceptibly (or not at all) in the absence of the enzyme.

The efficiency of an enzyme's activity is often measured by the turnover rate, which measures the number of molecules of compound upon which the enzyme works per molecule of enzyme per second. Carbonic anhydrase, which removes carbon dioxide from the blood by binding it to water, has a turnover rate of 10 6 . That means that one molecule of the enzyme can cause a million molecules of carbon dioxide to react in one second.

Most enzymatic reactions occur within a relatively narrow temperature range (usually from about 30°C to 40°C), a feature that reflects their complexity as biological molecules. Each enzyme has an optimal range of pH for activity; for example, pepsin in the stomach has maximal reactivity under the extremely acid conditions of pH 1–3. Effective catalysis also depends crucially upon maintenance of the molecule's elaborate three-dimensional structure. Loss of structural integrity, which may result from such factors as changes in pH or high temperatures, almost always leads to a loss of enzymatic activity. An enzyme that has been so altered is said to be denatured.

Like other proteins, enzymes consist of chains of amino acids linked together by peptide bonds. An enzyme molecule may contain one or more peptide bond or polypeptide chains. The sequence of amino acids within the polypeptide chains is characteristic for each enzyme and is believed to determine the unique three-dimensional conformation in which the chains are folded. This conformation, which is necessary for the activity of the enzyme, is stabilized by interactions of amino acids in different parts of the peptide chains with each other and with the surrounding medium. These interactions are relatively weak and may be disrupted readily by high temperatures, acid or alkaline conditions, or changes in the polarity of the medium. Such changes lead to an unfolding of the peptide chains ( denaturation ) and a concomitant loss of enzymatic activity, solubility, and other properties characteristic of the native enzyme.

Many enzymes contain an additional, nonprotein component, termed a coenzyme. This may be an organic molecule, often a vitamin derivative, a metal ion ( copper and zinc for some of the enzymes in the snail secretion) or an organic (often metal-containing) group.

The coenzyme, in most instances, participates directly in the catalytic reaction. For example, it may serve as an intermediate carrier of a group being transferred from one substrate to another. Some enzymes have coenzymes that are tightly bound to the protein and difficult to remove, while others have coenzymes that dissociate readily. When the protein moiety and the coenzyme are separated from each other, neither possesses the catalytic properties of the original conjugated protein (the holoenzyme).

By simply mixing the protein moiety and the coenzyme together, the fully active holoenzyme can often be reconstituted. The same coenzyme may be associated with many enzymes which catalyze different reactions. It is thus primarily the nature of the protein moiety rather than that of the coenzyme which determines the specificity of the reaction.

The enzyme-cofactor combination provides an active configuration, usually including an active site into which the substance (substrate) involved in the reaction can fit. Many enzymes are specific to one substrate. If a competing molecule blocks the active site or changes its shape, the enzyme's activity is inhibited. If the enzyme's configuration is destroyed its activity is lost.

Enzymes are classified by the type of reaction they catalyze: (1) oxidation-reduction, (2) transfer of a chemical group, (3) hydrolysis, (4) removal or addition of a chemical group, (5) isomerization, and (6) binding together of substrate units (polymerization).

Enzymes catalyze all aspects of cell metabolism, including the digestion of food, in which large nutrient molecules (including proteins, carbohydrates, and fats) are broken down into smaller molecules; the conservation and transformation of chemical energy; and the construction of cellular materials and components. The fermentation of wine, leavening of bread, curdling of milk into cheese, and brewing of beer are all enzymatic reactions. The uses of enzymes in medicine include killing disease-causing microorganisms, promoting wound healing, and diagnosing certain diseases.