isoform: <biochemistry> A protein having the same function and similar (or identical sequence), but the product of a
different gene and usually) tissue specific. Rather stronger in implication than homologous.
Fluorescence results from a process that occurs when certain molecules (generally polyaromatic hydrocarbons or heterocycles)
called fluorophores, fluorochromes, or fluorescent dyes absorb light. The absorption of light by a population of these molecules
raises their energy level to a brief excited state. As they decay from this excited state, they emit fluorescent light. The
process responsible for fluorescence is illustrated by a simple electronic state diagram (Fig 2). Excitation When a photon
of energy, hνEX, supplied by an external source such as a lamp or a laser, is absorbed by a fluorophore, it creates
an excited, unstable electronic singlet state (S1). This process is distinct from chemiluminescence, in which the excited
state is created by a chemical reaction.