{"id":545,"date":"2022-10-10T10:24:56","date_gmt":"2022-10-10T08:24:56","guid":{"rendered":"https:\/\/modafinil.pl\/sklep\/l-tyrosine-l-tyrosine-tyrosine-purity-%e2%89%a5-99-1000mg\/"},"modified":"2026-10-03T06:11:58","modified_gmt":"2026-10-03T04:11:58","slug":"l-tyrosine-2","status":"publish","type":"product","link":"https:\/\/modafinil.pl\/en\/sklep\/l-tyrosine-2\/","title":{"rendered":"L-Tyrosine (CAS 60-18-4) \u2014 laboratory reagent 1000 mg, purity \u2265 99%"},"content":{"rendered":"

(2S)-2-Amino-3-(4-hydroxyphenyl)propanoic acid<\/strong>, crystalline powder, 1000 mg pack (sachet). Material intended exclusively for laboratory and analytical in vitro research<\/strong>. This product is not intended for human or animal consumption<\/strong>; it is not a medicinal product, food supplement, foodstuff or cosmetic.<\/p>\n

Three different entities that must not be confused<\/h2>\n

With proteinogenic amino acids, separating the layers is skipped more often than with controlled substances \u2014 yet it is just as important. The same chemical name functions simultaneously as a natural constituent of proteins, as a component of food products sold for oral use and as a laboratory material. Three contexts, three different quality regimes and different intended uses:<\/p>\n\n\n\n\n\n\n\n
Separating the layers: substance \u2014 food product \u2014 reagent<\/caption>\n
Entity<\/th>\nWhat it is<\/th>\nStatus<\/th>\n<\/tr>\n<\/thead>\n
Chemical substance
L-tyrosine, CAS 60-18-4<\/th>\n		A chemical concept \u2014 one of the twenty standard proteinogenic amino acids, a molecule with a defined structure and L spatial configuration. In itself it is neither a foodstuff nor a reagent; its status is conferred only by the form in which it has been manufactured, purified and described.<\/td>\n\u2014<\/td>\n<\/tr>\n
Food supplement \/ food product
commercial preparations containing tyrosine<\/th>\n		A form intended for consumption: a defined presentation (tablets, capsules, powder for dissolving in water), labelling compliant with food law, serving information on the pack. It is precisely such preparations \u2014 or a controlled dietary intake of tyrosine in study participants \u2014 that the studies on metabolism and biosynthesis cited further on this page concern.<\/strong><\/td>\nthe material offered here is not one<\/strong><\/td>\n<\/tr>\n
Chemical reagent
material offered on this page<\/th>\n		Material for laboratory and analytical work. It does not have, and cannot have, authorisation as a foodstuff<\/strong> \u2014 it is not accompanied by food labelling, serving information or documentation intended for products for consumption.<\/td>\nanalytics, chemistry, reference standards<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The consequence is unambiguous.<\/strong> The data on metabolism and biosynthesis cited further on this page come from biochemical studies conducted in cell models and laboratory animals, or from controlled human nutritional physiology studies in which tyrosine was a dietary component or the compound under investigation \u2014 never using the analytical reagent described on this page<\/strong>. The material offered here has not been and is not studied as a food ingredient or as a substance for consumption, and none of the results cited transfers to this reagent.<\/p>\n

Reagent identification sheet<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Registry data and identifiers \u2014 L-tyrosine<\/caption>\n
Systematic name (IUPAC)<\/th>\n(2S)-2-amino-3-(4-hydroxyphenyl)propanoic acid<\/td>\n<\/tr>\n
Common name<\/th>\nL-tyrosine (tyrosyl \u2014 name of the residue in a peptide chain)<\/td>\n<\/tr>\n
CAS number<\/th>\n60-18-4<\/td>\n<\/tr>\n
Molecular formula<\/th>\nC9<\/sub>H11<\/sub>NO3<\/sub><\/td>\n<\/tr>\n
Molar mass<\/th>\n181.19 g\u00b7mol\u22121<\/sup><\/td>\n<\/tr>\n
Monoisotopic mass<\/th>\n181.0739 Da<\/td>\n<\/tr>\n
InChIKey<\/th>\nOUYCCCASQSFEME-QMMMGPOBSA-N<\/td>\n<\/tr>\n
SMILES<\/th>\nC1=CC(=CC=C1C[C@@H](C(=O)O)N)O<\/td>\n<\/tr>\n
PubChem CID<\/th>\n6057<\/a><\/td>\n<\/tr>\n
ChEMBL<\/th>\nCHEMBL3659228<\/td>\n<\/tr>\n
Form<\/th>\ncrystalline powder, white to off-white<\/td>\n<\/tr>\n
Purity<\/th>\n\u2265 99%<\/td>\n<\/tr>\n
Intended use<\/th>\nresearch reagent \u2014 not for human or animal consumption<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Lineage of the molecule: from cheese casein to a standard proteinogenic amino acid<\/h2>\n

The name \u201ctyrosine\u201d derives from the Greek tyros<\/em> \u2014 cheese. The etymology is no accident: the compound was first isolated in 1846 by the German chemist Justus von Liebig<\/strong> from casein, the principal protein of cheese, in the course of work on the hydrolysis products of proteins. This was a period of intensive research into the breakdown of proteins into their constituent \u201cbuilding blocks\u201d \u2014 by the same route of acidic or alkaline hydrolysis, most of the remaining standard amino acids were isolated over the following decades.<\/p>\n

Phenylalanine as precursor: the enzyme that adds a hydroxyl group<\/h3>\n

In mammals, tyrosine is not obtained solely from food \u2014 it is also formed from L-phenylalanine<\/a> in a reaction catalysed by the enzyme phenylalanine hydroxylase<\/strong>, which attaches a hydroxyl group to the aromatic ring. A disturbance of this pathway \u2014 deficiency or absence of enzyme activity \u2014 underlies phenylketonuria, a disease first described by the Norwegian physician Ivar Asbj\u00f8rn F\u00f8lling in 1934. A biochemical characterisation of the recombinant human enzyme was given by Ledley et al. [6<\/a>], and M\u00fcller and co-workers showed, in a paper published in PNAS<\/em>, that in adult humans the kidney is an important site of this conversion [5<\/a>]. For this reason tyrosine is classified as a conditionally essential<\/strong> amino acid \u2014 the organism can produce it, but only provided there is a sufficient supply of phenylalanine and a functional enzyme.<\/p>\n

The further pathway: starting point for catecholamines and thyroid hormones<\/h3>\n

This is solely a description of a biochemical pathway occurring in the organism, not information about the action of the reagent offered.<\/strong> Tyrosine is the substrate for the enzyme tyrosine hydroxylase<\/strong>, which catalyses the step regarded as rate-limiting for the entire catecholamine biosynthesis pathway \u2014 leading via L-DOPA<\/a> to dopamine, noradrenaline and adrenaline. The regulation of this enzyme in the central nervous system was reviewed by Masserano and Weiner [7<\/a>]. A separate pathway, unrelated to tyrosine hydroxylase, is the use of tyrosine as a structural core in the biosynthesis of thyroid hormones \u2014 Edward C. Kendall isolated thyroxine, built on the tyrosine skeleton, in 1914. None of these pathways is a property conferred by the analytical reagent<\/strong> \u2014 they are processes occurring in the living organism using endogenous or dietary tyrosine, not the material offered here for laboratory purposes.<\/p>\n

Timeline<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Timeline: from isolation to modern analytics<\/caption>\n
1846<\/th>\nJustus von Liebig isolates tyrosine from cheese casein; hence the name from the Greek tyros<\/em><\/td>\n<\/tr>\n
2nd half of the 19th c.<\/th>\ntyrosine counted among the standard proteinogenic amino acids; development of methods for the hydrolysis and identification of amino acids<\/td>\n<\/tr>\n
1914<\/th>\nEdward C. Kendall isolates thyroxine \u2014 a thyroid hormone built on the tyrosine skeleton<\/td>\n<\/tr>\n
1934<\/th>\nIvar Asbj\u00f8rn F\u00f8lling describes phenylketonuria \u2014 a disease associated with impaired conversion of phenylalanine to tyrosine<\/td>\n<\/tr>\n
1983<\/th>\nreview of tyrosine hydroxylase regulation in the central nervous system [7<\/a>]<\/td>\n<\/tr>\n
1987<\/th>\nbiochemical characterisation of recombinant phenylalanine hydroxylase [6<\/a>]<\/td>\n<\/tr>\n
1994<\/th>\ndescription of tyrosine racemisation in the proteins of the ageing eye lens as a model of racemisation chemistry [4<\/a>]<\/td>\n<\/tr>\n
1997<\/th>\nmethod for trace determination of the positional isomers meta- and ortho-tyrosine by GC-MS [8<\/a>]<\/td>\n<\/tr>\n
2000<\/th>\ndemonstration of the kidney as a site of phenylalanine-to-tyrosine conversion in adult humans [5<\/a>]<\/td>\n<\/tr>\n
2009<\/th>\nsynthetic method limiting racemisation in Suzuki couplings of tyrosine derivatives [3<\/a>] and an HPLC method with fluorescence detection for determining tyrosine in plasma and dried blood [1<\/a>]<\/td>\n<\/tr>\n
2011<\/th>\ntrace analysis of D-tyrosine by microchip electrophoresis with fluorescence detection [2<\/a>]<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Chemistry: why the L configuration and not D, and why the para position matters<\/h2>\n

The stereogenic centre at the alpha carbon<\/h3>\n

As in every chiral proteinogenic amino acid, the stereogenic centre of tyrosine is the alpha carbon<\/strong> \u2014 it bears four different substituents: an amino group, a carboxyl group, a hydrogen atom and a side chain with a 4-hydroxyphenyl ring. The naturally occurring form incorporated into proteins has the L<\/strong> configuration (corresponding to S<\/em> in the R\/S nomenclature for this molecule); its mirror image, D-tyrosine<\/strong>, is not used in mammalian protein synthesis, but appears as a biochemical marker and is the subject of separate analytical methods \u2014 trace analysis of D-tyrosine in biological samples by microchip electrophoresis with fluorescence detection was described by Huang et al. [2<\/a>].<\/p>\n

Racemisation: why control of chirality matters in practice<\/h3>\n

The alpha carbon of amino acids, including tyrosine, can undergo racemisation \u2014 slow conversion to the D form, spontaneous or catalysed \u2014 under conditions of high temperature, a strongly alkaline environment or in the presence of certain synthetic catalysts. The phenomenon has been described both as a marker of ageing of structural proteins \u2014 racemisation of tyrosine in the insoluble protein fraction of the ageing eye lens [4<\/a>] \u2014 and as a practical synthetic problem: in Suzuki couplings of aryl derivatives of tyrosine, an appropriate choice of ligand (SPhos) made it possible to limit undesired racemisation of the product [3<\/a>]. For a laboratory using this reagent the conclusion is practical: declared chemical purity is not the same as enantiomeric purity<\/strong> \u2014 confirming the L\/D ratio requires a chiral method, not merely a total assay.<\/p>\n

Why the position of the substituent matters: para-, not meta- or ortho-tyrosine<\/h3>\n

The hydroxyl group in tyrosine is located at the para<\/strong> position of the phenyl ring. This is not the only chemically possible position: oxidation of phenylalanine by hydroxyl radicals can lead to the formation of positional isomers \u2014 meta-tyrosine and ortho-tyrosine<\/strong> \u2014 regarded as markers of oxidative protein damage, distinct from the normal, para-substituted protein tyrosine. A method for trace determination of both isomers by gas chromatography\u2013mass spectrometry with electron-capture ionisation was described by Blount and Duncan [8<\/a>]. For analytics this means that merely detecting \u201ctyrosine\u201d in a mass spectrum does not settle the position of the substituent at the same molecular mass \u2014 distinguishing positional isomers requires chromatographic separation before detection.<\/p>\n

Physicochemical characteristics<\/h3>\n\n\n\n\n\n\n\n\n\n\n
Computed descriptors and their analytical significance<\/caption>\n
Parameter<\/th>\nValue<\/th>\nImplication<\/th>\n<\/tr>\n<\/thead>\n
Partition coefficient (logP)<\/th>\n\u22122.3<\/td>\nstrongly hydrophilic molecule \u2014 short retention time in classical RP-HPLC without derivatisation or ion-pairing<\/td>\n<\/tr>\n
Topological polar surface area<\/th>\n83.6 \u00c52<\/sup><\/td>\nhigh \u2014 reflects the simultaneous presence of phenolic, amino and carboxyl groups<\/td>\n<\/tr>\n
Hydrogen bond donors<\/th>\n3<\/td>\nphenolic OH group, NH2<\/sub> group and carboxyl group<\/td>\n<\/tr>\n
Hydrogen bond acceptors<\/th>\n4<\/td>\nphenolic oxygen, amino nitrogen, two carboxyl oxygens<\/td>\n<\/tr>\n
Melting point (with decomposition)<\/th>\n343.5 \u00b0C<\/td>\ntypical of amino acids \u2014 thermal decomposition precedes true melting<\/td>\n<\/tr>\n
Solubility<\/th>\npoor in water and in common organic solvents; good in dilute solutions of acids and bases<\/td>\nprepare stock solutions by acidification or alkalinisation, not in pure water<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Nomenclature and synonyms<\/h2>\n

One molecule, many forms of notation in chemical databases and catalogues \u2014 useful when building a bibliographic query or checking that a batch matches an order:<\/p>\n