Urea is the principal end product of nitrogen metabolism in most mammals, formed by the enzymatic reactions of the Kreb's cycle. Urea is a mild agent usually used in the solubilization and denaturation of proteins. It is also useful for renaturing proteins from samples already denatured…

Tris have been useful as buffers in a wide variety of biological systems. It has been used as a starting material for polymers, oxazolones (with carboxylic acids) and oxazolidines (with aldehydes). It does not precipitate calcium salts and is of value in maintaining solubility of manganese salts.…