What are the general properties of amino acids?

Amino acids are colorless, crystalline solid substances. All amino acids have a high melting point between 200°C-300°C due to their ionic property. They also have a very high boiling point. Amino acids decompose on heating to high temperatures. Most amino acids are tasteless. A few amino acids such as glycine and alanine are sweet and some such as arginine are bitter in taste. 

The solubility of amino acids is dependent on a number of factors including temperature, polarity, nature or pH of the solvent and iso-electric point. Most are soluble in water, insoluble in organic solvents, and slightly soluble in alcohol. pH of the solvent and R-group of amino acids play a key role in solubility. 

All amino acids are amphoteric in nature. They can act as both an acid and base because of the presence of the two amine and carboxylic groups. All amino acids except glycine are optically active.