Freely soluble in formic acid, very slightlysoluble in water,practically insoluble in ethanol and in . Dissolve in dilute hydrochloric acid and in dilute nitric acid. Aside from being a proteinogenic amino acid, tyrosine has a special role by virtue of the phenol functionality. It occurs in proteins that are part of signal transduction processes. L-tyrosine functions as a receiver of phosphate groups that are transferred by way of protein kinases (so-called receptor tyrosine kinases). Phosphorylation of the hydroxyl group changes the activity of the target protein.China H&Z® L-tyrosine is a precursor to neurotransmitters and increasesplasma neurotransmitter levels (particularly and )but has little if any effect on mood.The effect on mood is more noticeable in humans subjected to stressful conditions.