Enzymes: Biological Catalysts and Metabolic Processes

• Enzymes are proteins that function as biological catalysts.
• Enzymes accelerate chemical reactions.
• Substrates are the molecules that enzymes act upon.
• Enzymes convert substrates into different molecules known as products.
• Enzyme catalysis is needed for almost all metabolic processes in the cell to occur at rates fast enough to sustain life.
• Metabolic pathways rely on enzymes to catalyze individual steps.
• Enzymology is the study of enzymes.
• Processes based on the action of enzymes, like alcoholic fermentation, use of yeast for baking, and cheese production, have been used for thousands of years.
• The first evidence of enzymes came in 1833 from French chemist Anselme Payen's experiments, using barley seedling extracts to produce large quantities of sugar from starch.
• The existence of a "ferment" was postulated, originating from the Latin term "fermentum," meaning fermentation or leaven.
• In 1830-1840, Swedish chemist Jöns Jakob Berzelius proposed that this ferment had a catalytic effect, on which the process of fermentation was based.
• Friedrich Wilhelm Kühne introduced the term "enzyme" in 1878, derived from the Greek word "énzymon," meaning leaven or yeast.
• Emil Fischer, the 1902 Nobel Prize winner in Chemistry for work on sugar chemistry, postulated the lock-and-key principle in 1890.
• The lock-and-key principle explains a substrate fitting into the active center of an enzyme like a key fits into a lock.
• Eduard Buchner is the founder of modern enzymology.
• Buchner proved that fermentation can occur without living cells, catalyzed by a protein-containing substance called zymase and was awarded the Nobel Prize in Chemistry in 1907.
• James B. Sumner proved in 1926 that the enzyme urease is a pure, crystallizable protein.
• John H. Northrop confirmed this for pepsin, trypsin, and chymotrypsin.
• Sumner and Northrop received the Nobel Prize in Chemistry in 1946 together with Wendell M. Stanley.
• Enzymes can work actively in vitro, which makes them useful in industrial processes.
• Enzymes are nature's own biocatalysts because they are complex protein molecules produced by living organisms to catalyze the biochemical reactions required to sustain life.
• Mostly enzymes are proteins, but RNA and antibodies can also act as catalysts known as ribozymes and abzymes, respectively.
• Literature suggests that enzymes catalyze over 5000 biochemical reaction types.
• Enzymes accelerate biochemical reactions up to 10^17-fold.
• Enzymes maintain the metabolism of all living organisms.
• Most enzymes need a small molecule called cofactors or coenzymes to perform activity as a catalyst.
• Cofactors are non-proteinaceous chemical compounds bound to an inactive protein part of an enzyme, or apoenzyme.
• Cofactors increase the biological activity of the enzyme needed for its function.
• The active complex of apoenzyme (protein part) with cofactor (coenzyme or prosthetic group) is called holoenzyme.
• A cofactor is a "helper molecule" which assists in biochemical transformations.
• Coenzymes and prosthetic groups are the two types of cofactors.
• Coenzymes are a specific type of cofactor and are organic molecules that bind to enzymes and help in their functions.

Enzymes are proteins accelerating chemical reactions as biological catalysts. They act on substrates, converting them into products necessary for metabolic processes. Enzymology, the study of enzymes, reveals their importance in sustaining life and various processes like fermentation and cheese production.