Tyrosine was found in casein by Lipidge in 1846. It is a white crystalline powder, which crystallizes from water as needle or sheet. It has a relative density of 1.456(20 ° C) , an isoelectric point of 5.66, a UV absorption capacity, and a maximum optical absorption at a wavelength of 274 nm. It can reduce phosphomolybdate-phosphotungstic acid reagent (Hungarian forint reagent) . Melting Point: levosome decomposes at 290-295 ° C (slow heating) , 314-318 ° C (fast heating) , racemic at 290-295 ° C (slow heating) , Chemicalbook at 340 ° C (fast heating) . Soluble in water, ethanol, acid and alkali, insoluble in ether. The reaction of tyrosinase with the aqueous solution of Dextran was red. The triboluminescence of the left-handed barium dihydroxide and its transformation into racemes at 170 a ° C by heating with the aqueous solution of diazobenzene sulfonic acid (diazobenzenesulfonic acid) , it is purple or red in reaction with boiling dilute acetic acid and Sodium Nitrite acid, yellow in reaction with warm nitric acid, and dark orange in reaction with titanium dioxide acid. Natural tyrosine is a levo-form, which can be obtained by protein hydrolysis and purification.