Question

Discuss dissociations and associations constants.

Answer 1

Dissociation in chemistry and biochemistry is a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into smaller particles such as atoms, ions or radicals, usually in a reversible manner. For instance, when an acid dissolves in water, a covalent bond between an electronegative atom and a hydrogen atom is broken by heterolytic fission, which gives a proton (H+) and a negative ion. Dissociation is the opposite of association or recombination

Answer 2

koff is the rate constant of dissociation of the drug from the receptor

kon is the rate constant of association of the drug to the receptor

Dissociation constant (Kd ) is the rate constant of dissociation at equilibrium, defined as the ratio koff / kon

Association constant (ka or Ka ) is the opposite of Kd

When Ka is high, Kd is low, and the drug has a high affinity for the receptor (fewer molecules are required to bind 50% of the receptors)

Affinity in chemistry is the tendency of dissimilar chemical species to form chemical compounds.

The major factors which affect affinity and dissociation constant in clinical pharmacology are temperature and the presence of a catalyst.