^{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. It 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.}

^{Medical use:
Tyrosine is a precursor to neurotransmitters and increases plasma neurotransmitter levels (particularly dopamine and norepinephrine)but has little if any effect on mood.The effect on mood is more noticeable in humans subjected to stressful conditions}

N-Acetyl-L-tyrosine is an important fine chemical intermediate, widely used in medicine, pesticides, chemical industry and other fields

Qingdao Sigma Chemical Co., Ltd.is a global chemical industry manufacturers and suppliers of pharmaceuticals and intermediates, food and feed additives, herbal extracts, agrochemicals and fine chemicals etc.

The aim of Qingdao Sigma Chemical Co., Ltd is a quality policy that "Elements in the system all have been satisfied, Personnel has been trained; Every batch of material is checked, Each procedure guarantees the quality; Every bag of our products is top grade, Service is thoughtful all the time, quality and reputation to increase market share and promote enterprise development. The quality, colors and forms of our products have reached a high level in related chemical industry, which relies on characteristic and advanced processing technology and it has gained a high and reliable reputation from customers at both quality and services.