good question, although it'd help to know the context of your question...
i'll answer this way - to start, ';enamel'; is not a type of paint. enamel is a descriptive term that relates to the hardness or impermeability of a specific paint product. others have mentioned that enamel is not water soluble or that it contains solvents harmful to the environment...neither of these statements are completely true. enamel products may be solvent or water soluble, latex or oil (alkyd).
because enamels dry harder than non-enamel finishes - they are rigid as a paint film. because they are more rigid you wouldn't want to use them in environments where flexibility is necessary - or where the surface to be painted is subject to expansion and contraction (such as wood siding on your house)...over time the hard enamel finishes would crack and peel due to their inability to expand and contract with the substrate.
conversely, if you're painting a surface that requires maximum abrasion resistance (floors, machinery etc) you would need a finish product that dries hard and not flexible.
although enamels typically have a sheen, it is not correct to say that all enamels are high gloss or that they necessarily have any sheen at all. because enamel describes the products hardness (or impermeability), these products are usually job or project specific - example: floor enamel (latex or oil), rust inhibiting enamel (latex or oil), machinery or equipment enamel (latex or oil)...interior wall paint products such such as ';interior latex semi-gloss enamel'; usually refers more to the products impermeability than to its actual hardness - so these products may be a little more impervious to moisture (steam/condensation) penetration and/or more resistant to staining than typical non-enamel type wall paints. you would then typically want to use an ';enamel'; type (latex) paint for interior rooms such as kitchens and baths.
...and there are such things as flat enamels (both latex and oil). these products have little or no sheen but are still hard, impervious coatings.
i hope this information is more helpful than confusing but keep this in mind when painting or considering what type of paint to buy...not all ';enamels'; are oil based or high sheened (glossy) and not all oil base products are enamels (e.g. oil base house paint is not an enamel) - and latex products may - or may not be enamels. for better more complete information for your specific projects, see your local independent paint store and ask him/her for their advice and recommendations - stores like home depot and lowes may have the products you need but too often times they don't have the experienced personnel necessary to help you with specific questions or concerns.
good luck on your projects...
p.s. - and by the way, latex products are NOT made up of rubber or rubber containing materials...the resin used in latex products are usually vinyl or acrylic (or a combination of both) and are actually petro-chemical derivatives - not rubber or natural resins. the term ';latex';, as it relates to paint, came from the appearance of the paint film when magnified many many times - when viewed through powerful magnification, it has the appearance of lattice panels - thus the name ';latex';
....trust me, sharing that little tidbit of trivial information will make you the hit of some pretty nerdy parties...What is the specific property of enamel paint ?
Enamel paint has been recently used to distinguish it from latex paint. Latex paint is actually made of rubber-based material that is water-soluble, while enamel paint is not water-soluble and must be dissolved in pollution-causing organic solvents like toluene and acetone to dissolve it. Some municipals have banned the sale of enamel paint for this reason.What is the specific property of enamel paint ?
It's not water soluable