Description
Tyrosine is one of the proteinogenic amino acids that looks trivial on paper and turns awkward on the bench. The questions below are the ones that decide whether a delivered batch behaves the way a method assumes it will. See also our reagent-grade material: Pramiracetam czystość substancji ≥ 99% 1000mg..
What exactly is on the certificate?
Registry number 60-18-4, molecular formula C9H11NO3, formula weight 181.19 g/mol, systematic name (S)-2-amino-3-(4-hydroxyphenyl)propanoic acid. In the container it is a white crystalline powder. The molecule carries three ionisable groups — a carboxylic acid, a primary amine and a phenolic hydroxyl — and in the solid state it exists as a zwitterion rather than a neutral species.
Why is it so difficult to dissolve in water?
Because the zwitterionic lattice is held together by strong ionic and hydrogen-bonded interactions, and the flat phenol ring stacks efficiently on top of that. Among the standard amino acids, tyrosine sits at the poorly soluble end in neutral water. Solubility rises steeply in dilute acid or dilute alkali, where one charged group is neutralised and the lattice loosens; that route, rather than heating, is the usual way to a concentrated stock.
Which grade is the right one?
Suppliers list this substance across several distinct grades: reagent, cell-culture tested, pharmacopoeial reference material against European and United States Pharmacopeia monographs, food grade, and certified reference material produced under ISO 17034. They are the same molecule and different products. A cell-culture grade carries endotoxin and elemental limits that a reagent grade does not, and quietly substituting one for the other changes the experiment.
How is chirality controlled?
The alpha carbon is a stereocentre, so three materials share the same common name: the L form, the D form and the racemic DL mixture. Optical rotation measured under the conditions named in the monograph is the routine check, and chiral chromatography is the confirmatory one. A purity figure from an achiral method says nothing at all about enantiomeric composition.
What is worth checking on receipt?
Appearance, loss on drying, and identity by infrared spectrum compared against a reference. The phenolic ring gives strong near-ultraviolet absorbance, which makes identity and assay by ultraviolet detection straightforward, and it is the same property exploited when protein concentration is estimated spectroscopically.
How should it be stored?
Sealed, dry and out of light at ordinary laboratory temperature. The phenol is the vulnerable group: prolonged exposure to light and air in the presence of trace metals darkens the powder, and any discolouration is reason enough to re-confirm identity before the lot is used again. See also our reagent-grade material: Phenylpiracetam / Phenylpiracetam, Purity ≥ 99%, 1.
- CAS 60-18-4, C9H11NO3, 181.19 g/mol, zwitterionic crystalline solid.
- Poorly soluble in neutral water; go through dilute acid or dilute alkali instead.
- Grade matters — reagent, cell-culture, pharmacopoeial and food grades are not interchangeable.
- L, D and DL materials exist; only a chiral method separates them.
- Store sealed, dry and dark; discolouration signals oxidation at the phenol.
Related reagents
- Phenylpiracetam / Phenylpiracetam, Purity ≥ 99%, 1000mg
- Pramiracetam czystość substancji ≥ 99% 1000mg.
- Phenylpiracetam/Phenylpiracetam, Reinheit ≥ 99%, 1000mg
- ALCAR / Acetyl-L-Carnitine – Purity ≥ 99% net weight 1000mg.
Selected literature
Animal and in vitro studies indexed in PubMed; no human-use guidance is provided here.
- Mazzocco MM Cognition and tyrosine supplementation among school-aged children with phenylketonuria 1992, American journal of diseases of children (19. PMID 1415060
- Solon-Júnior LJF The effect of tyrosine supplementation on whole-body endurance performance in physically active population: A systematic review and meta-analysis including GRADE qualification 2023, Journal of sports sciences. PMID 38290812
- Jongkees BJ Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands–A review 2015, Journal of psychiatric research. PMID 26424423
Reagent classification. The material must not be used in humans. It is not a veterinary product either. This is a high-purity laboratory reagent intended for analytical work by HPLC and GC-MS. Not a medicine, medical device or food product.
