ENZYMES & VITAMINS

Enzyme specificity is the extent to which an enzyme’s activity is restricted to a specific substrate, a specific group of substrates, a specific type of chemical bond, or a specific type of chemical reaction. Absolute specificity refers to an enzyme that catalyzes only one reaction, such as catalase, which converts hydrogen peroxide (H2O2) to O2 and H2O.

Coenzyme A is required in the metabolism of carbohydrates, lipids, and proteins, involved in the transfer of acetyl groups between molecules.

An enzyme is a compound, usually a protein, that acts as a catalyst for a biochemical reaction, speeding up the reaction and causing cellular reactions to occur millions of times faster than uncatalyzed reactions. Enzymes differ from nonbiochemical catalysts in size, being much larger, and in their activity, as biochemical catalysts in the body are regulated by other substances present in the cell.

Feedback control is a process where the activation or inhibition of the first reaction in a sequence is controlled by a product of that reaction sequence. The final product D acts as a negative regulator for enzyme 1, inhibiting its activity at higher concentrations.

Biotin (B7) is involved in carboxylation reactions.

Megaloblastic anemia and peripheral neuropathy.

A zymogen is the inactive precursor of a proteolytic enzyme, produced to prevent tissue damage. Zymogens are activated by enzymatic removal of part of their structure, altering their three-dimensional shape and active site conformation.

Vitamin A forms rhodopsin, a visual pigment involved in light-to-nerve impulse conversion, regulates cell differentiation, and participates in reproduction and growth.

Pellagra: dementia, dermatitis, diarrhea.

Coenzymes are small organic molecules that serve as cofactors in conjugated enzymes and are synthesized within the human body using building blocks obtained from other nutrients. Cofactors are generally small organic molecules or inorganic ions that assist in enzyme activity, and they can be permanently bonded to the enzyme's amino acid portion.

Vitamin C acts as a general antioxidant by recharging spent enzymes that contain metal atoms and regenerating the active form of vitamin E. It also functions as a cosubstrate in the formation of collagen and is needed for the synthesis of Hydroxyproline and Hydroxylysine.

Vitamin A maintains the health of skin and internal linings, preventing dryness and hardening.

Scurvy.

Reversible competitive inhibition occurs when a competitive enzyme inhibitor resembles the substrate and competes for the enzyme's active site, blocking substrate access and decreasing enzyme activity. Increasing substrate concentration can reduce competitive inhibition by allowing the substrate to bind more frequently to the active site.

Niacin occurs in food in two forms: nicotinic acid and nicotinamide, and it participates in oxidation-reduction reactions involving hydrogen transfer.

Vitamin D maintains normal blood calcium and phosphate levels, stimulates absorption from the gastrointestinal tract, aids in retention by the kidneys, and triggers calcium salt deposition into bones.

The active site is a relatively small part of an enzyme’s structure that is involved in catalysis, formed by groups from different parts of the protein chain(s). Electrostatic interactions, hydrogen bonds, and hydrophobic interactions help attract and bind substrate molecules.

The name thiamin comes from 'thio,' meaning 'sulfur,' and 'amine,' referring to the numerous amine groups present. Thiamin (B1) is involved in the decarboxylation of α-keto acids.

Only microorganisms can produce Vitamin B12; it cannot be made by plants, animals, birds, or humans.

It is involved in many redox reactions and the hydroxylation of collagen.

Temperature affects enzyme activity by influencing the kinetic energy of molecules; higher temperatures increase reaction rates until a point where the enzyme denatures, leading to decreased activity. When the temperature exceeds 40°C, it can initiate enzyme denaturation, leading to a loss of function that can be life-threatening.

Vitamin B6 is a collective term for pyridoxine, pyridoxal, and pyridoxamine, and it is involved in amino acid metabolism through amino group transfer.

Retinoids are preformed vitamin A forms, including retinal, retinol, and retinoic acid.

Rickets.

Slight alterations in pH or temperature, and vigorous shaking of an enzyme can destroy enzyme activity. Small changes in pH (less than one unit) can result in enzyme denaturation and subsequent loss of catalytic activity.

Riboflavin (B2) is involved in oxidation-reduction reactions involving hydrogen transfer, and its coenzymes FAD and FMN play a crucial role in these reactions.

Fat-soluble vitamins have structures that are more hydrocarbon-like, with fewer functional groups, making them nonpolar and enhancing their solubility in cell membranes.

Acute toxicity can cause drowsiness, headache, vomiting, stupor, skin peeling, and papilledema.

A holoenzyme is the active conjugated enzyme produced from an apoenzyme (the protein part) and a cofactor (the nonprotein part). An apoenzyme is the protein part of a conjugated enzyme that, by itself, does not have catalytic properties.

Many enzymes contain vitamins as part of their structure and vitamins often act as cofactors in conjugated enzymes. Vitamins are organic compounds essential in small amounts for proper human body functioning, obtained from dietary sources since the body cannot synthesize them.

Pantothenic Acid (B5) is involved in the metabolism of carbohydrates, lipids, and proteins through acetyl group transfer.

To ensure adequate prothrombin levels and to prevent hemorrhaging.

Reversible noncompetitive inhibition occurs when a noncompetitive enzyme inhibitor binds to a site other than the active site, altering the enzyme's structure and preventing proper catalysis, even if the substrate can still bind. Uncompetitive inhibitors bind only to the enzyme-substrate complex and not to the free enzyme.

The two most important members of the vitamin D family are Vitamin D3 (cholecalciferol) and Vitamin D2 (ergocalciferol), which maintain normal blood calcium and phosphate levels.

The two main forms of Vitamin K are Vitamin K1 (phylloquinone), found in plants, and Vitamin K2 (menaquinones), found in animals and synthesized by bacteria.

Abnormal enzyme activity in blood serum can indicate tissue damage and leakage of cellular contents into the bloodstream, aiding in the diagnosis of various diseases.

Vitamin B12 coenzymes participate in the transfer of alkyl groups and hydrogen atoms from one molecule to another.

Vitamin K is essential to the blood-clotting process.

Vitamin E acts as an antioxidant, scavenging free radicals and maintaining cellular respiration by donating hydrogen atoms to oxygen-containing free radicals.