{"id":542,"date":"2022-10-04T17:23:06","date_gmt":"2022-10-04T17:23:06","guid":{"rendered":"https:\/\/modafinil.pl\/sklep\/phenylalanine-l-phenylalanine-%e2%89%a5-99-1000mg\/"},"modified":"2026-10-03T04:11:57","modified_gmt":"2026-10-03T04:11:57","slug":"phenylalanine-l-phenylalanine-%e2%89%a5-99-1000mg","status":"publish","type":"product","link":"https:\/\/modafinil.pl\/en\/sklep\/phenylalanine-l-phenylalanine-%e2%89%a5-99-1000mg\/","title":{"rendered":"L-Phenylalanine (CAS 63-91-2) \u2014 laboratory reagent 1000 mg, purity \u2265 99%"},"content":{"rendered":"

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

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

The name “phenylalanine” tends to be used interchangeably in three different contexts \u2014 as a chemical concept, as a constituent of registered pharmaceutical preparations administered in hospital settings, and as a laboratory material. Separating these layers is just as important here as for the substances with a stronger regulatory profile in our catalogue:<\/p>\n\n\n\n\n\n\n\n
Separating the layers: substance \u2014 medicinal product \u2014 reagent<\/caption>\n
Entity<\/th>\nWhat it is<\/th>\nStatus<\/th>\n<\/tr>\n<\/thead>\n
Chemical substance
L-phenylalanine, CAS 63-91-2<\/th>\n		A chemical concept \u2014 one of the twenty proteinogenic amino acids, a building block of proteins. In itself it is neither a drug nor a reagent; its status is conferred only by the form in which it has been manufactured and authorised for marketing.<\/td>\n\u2014<\/td>\n<\/tr>\n
Medicinal product
constituent of parenteral nutrition solutions<\/th>\n		L-phenylalanine is a constituent of multi-component amino acid solutions for intravenous infusion, used in the parenteral nutrition of hospital patients. These preparations are manufactured under a GMP regime, at a strictly defined concentration, as part of a complex mixture of more than a dozen amino acids \u2014 never as a single substance.<\/td>\nclinical data on the administration of amino acids to patients concern this entity<\/strong><\/td>\n<\/tr>\n
Chemical reagent
the material offered here<\/th>\n		Material for laboratory and analytical work: standard, substrate, reference material. It does not have, and cannot have, authorisation for use in humans or animals<\/strong> \u2014 it has no pharmaceutical form, is not subject to a pharmaceutical manufacturing regime, and is not accompanied by medicinal product documentation.<\/td>\nanalytics, chemistry, reference standards<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The consequence is unambiguous.<\/strong> Data on the role of phenylalanine in the human body \u2014 its absorption, its conversion to tyrosine or the kinetics of its plasma concentration [1<\/a>] \u2014 come from physiological and clinical studies conducted either on phenylalanine contained in food or on registered pharmaceutical preparations administered under medical supervision<\/strong>. None of these studies was conducted using an analytical reagent<\/strong>, and none of these findings carries over to the material offered. The reagent is not a form in which the substance has ever been administered to humans for therapeutic or nutritional purposes, and it must not be used in such a way.<\/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-phenylalanine<\/caption>\n
Systematic name (IUPAC)<\/th>\n(2S)-2-amino-3-phenylpropanoic acid<\/td>\n<\/tr>\n
Common name<\/th>\nL-phenylalanine (L-Fenyloalanina)<\/td>\n<\/tr>\n
CAS number<\/th>\n63-91-2<\/td>\n<\/tr>\n
Molecular formula<\/th>\nC9<\/sub>H11<\/sub>NO2<\/sub><\/td>\n<\/tr>\n
Molar mass<\/th>\n165.19 g\u00b7mol\u22121<\/sup><\/td>\n<\/tr>\n
Monoisotopic mass<\/th>\n165.0790 Da<\/td>\n<\/tr>\n
InChIKey<\/th>\nCOLNVLDHVKWLRT-QMMMGPOBSA-N<\/td>\n<\/tr>\n
SMILES<\/th>\nC1=CC=C(C=C1)C[C@@H](C(=O)O)N<\/td>\n<\/tr>\n
PubChem CID<\/th>\n6140<\/a><\/td>\n<\/tr>\n
ChEMBL<\/th>\nCHEMBL373882<\/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 a green urine sample to newborn screening worldwide<\/h2>\n

Phenylalanine as a chemical compound was already known to chemists in the 19th century, as one of the amino acids that make up proteins. Its actual lineage as a substance of distinct medical significance, however, begins only in 1934, in Oslo \u2014 and not in a chemistry laboratory, but with the observation of two children.<\/p>\n

A mother, two children and an unusual urine odour<\/h3>\n

A Norwegian physician drew the attention of the chemist Asbj\u00f8rn F\u00f8lling<\/strong> to the unusual odour of the urine of her two children with intellectual disability. F\u00f8lling examined the samples chemically using a simple reaction with iron(III) chloride \u2014 a test that typically gives a violet colour with ketone bodies. Instead, he obtained a persistent green colour<\/strong>, the signal of a compound he could not immediately identify. Further analysis led him to phenylpyruvic acid<\/strong> \u2014 a product of phenylalanine metabolism that accumulates in the body when the enzyme converting this amino acid into tyrosine is lacking. The history of this discovery and the circumstances in which it came about were reconstructed by Centerwall [2<\/a>] and by F\u00f8lling himself in a memoir published sixty years later [3<\/a>].<\/p>\n

In 1934 F\u00f8lling described this disease entity as “imbecillitas phenylpyruvica” \u2014 a name later replaced by the term phenylketonuria<\/strong>. A detailed historical analysis of the discovery, including F\u00f8lling’s role and the context of Norwegian medicine in the 1930s, was presented by Christ [4<\/a>], and a synthesis of a hundred years of screening research by Woolf [5<\/a>].<\/p>\n

From symptom to population screening<\/h3>\n

For three decades after the discovery, phenylketonuria was diagnosed only after irreversible damage to the central nervous system had occurred. This was changed by the introduction of the Guthrie test<\/strong> \u2014 a microbiological bacterial growth inhibition assay performed on a drop of blood taken from a newborn, making it possible to detect an elevated phenylalanine concentration before any symptoms appear<\/strong>. Early descriptions of the method and experience with its implementation in population screening programmes were published by Partington [6<\/a>] and Blumenfeld [7<\/a>]. Phenylketonuria thus became one of the first diseases covered by universal newborn screening<\/strong> worldwide \u2014 a model later extended to dozens of other metabolic disorders.<\/p>\n

Timeline<\/h2>\n\n\n\n\n\n\n\n\n\n
Timeline: from the discovery of the disease to contemporary determination methods<\/caption>\n
1934<\/th>\nAsbj\u00f8rn F\u00f8lling identifies phenylpyruvic acid in the urine of two children with intellectual disability; describes “imbecillitas phenylpyruvica” [2<\/a>][4<\/a>]<\/td>\n<\/tr>\n
1950s<\/th>\nintroduction of a diet with controlled phenylalanine content as the first effective intervention<\/td>\n<\/tr>\n
1960s<\/th>\nimplementation of the Guthrie test in population newborn screening [6<\/a>][7<\/a>]<\/td>\n<\/tr>\n
1997<\/th>\nsystematic comparison of four methods for determining phenylalanine in screening samples [8<\/a>]<\/td>\n<\/tr>\n
2014<\/th>\nAmerican guideline for the diagnosis and management of phenylalanine hydroxylase deficiency [9<\/a>]<\/td>\n<\/tr>\n
2017<\/th>\ncomplete European guidelines for the diagnosis and treatment of phenylketonuria [10<\/a>]<\/td>\n<\/tr>\n
2023\u20132024<\/th>\ndevelopment of tandem mass spectrometry (LC-MS\/MS) in newborn screening, displacing the Guthrie test [11<\/a>][12<\/a>]<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The 2014 and 2017 guidelines [9<\/a>][10<\/a>] were developed independently on both sides of the Atlantic and reached convergent conclusions \u2014 for the laboratory, this signals that the phenylalanine determination methods described below are validated on an international scale, not in a single centre.<\/p>\n

Chemistry: the stereogenic centre at the \u03b1-carbon and what follows from it<\/h2>\n

Why S, not R, is the biologically relevant form<\/h3>\n

The \u03b1-carbon atom (C2) of phenylalanine bears four different substituents \u2014 an amino group, a carboxyl group, a hydrogen atom and a benzyl group \u2014 which makes it a stereogenic centre<\/strong>. The natural enantiomer incorporated into proteins has the S<\/strong> configuration and is designated L-phenylalanine; the enantiomer with the R<\/strong> configuration, D-phenylalanine, has the same molecular formula and the same mass but is not a substrate of ribosomal protein synthesis in mammals<\/strong>. The two forms cannot be distinguished by achiral methods \u2014 this requires a chiral column or derivatisation with a chiral reagent. Methods for separating phenylalanine enantiomers were described by Lomenova et al., using achiral-chiral two-dimensional chromatography in a dietary supplement matrix [13<\/a>], and by Hsiao et al., determining phenylalanine enantiomers in mammalian plasma and urine by two-dimensional HPLC [14<\/a>].<\/p>\n

For the laboratory this has a practical consequence analogous to the one we describe for modafinil<\/a>: a total determination by an achiral method does not settle the enantiomeric purity<\/strong> of the material. The declaration “L-phenylalanine \u2265 99%” refers to chemical purity, not to the enantiomer ratio, unless the manufacturer states this separately.<\/p>\n

Isotopic labels and mass spectrometry<\/h3>\n

Phenylalanine labelled with stable isotopes (2<\/sup>H, 13<\/sup>C, 15<\/sup>N) is a standard tool of quantitative mass spectrometry \u2014 it serves as an internal standard in GC-MS and LC-MS\/MS methods, allowing the analyte signal to be distinguished from the biological matrix background by the mass difference. The methodology for determining isotopic ratios of L-leucine and L-phenylalanine by gas chromatography\/triple-stage quadrupole mass spectrometry was described by Schweer et al. [15<\/a>].<\/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>\nWhat follows from it<\/th>\n<\/tr>\n<\/thead>\n
Partition coefficient (logP, computed)<\/th>\n\u2248 \u22121.5<\/td>\na distinctly hydrophilic compound \u2014 short retention time in standard RP-HPLC without derivatisation<\/td>\n<\/tr>\n
Topological polar surface area<\/th>\n63.3 \u00c52<\/sup><\/td>\nmoderate, dominated by the amino and carboxyl groups<\/td>\n<\/tr>\n
Hydrogen bond donors<\/th>\n2<\/td>\namino group<\/td>\n<\/tr>\n
Hydrogen bond acceptors<\/th>\n3<\/td>\ncarboxyl oxygen and amino nitrogen<\/td>\n<\/tr>\n
Melting point<\/th>\n\u2248 283 \u00b0C (with decomposition)<\/td>\ntypical of free amino acids \u2014 the compound decomposes before classical boiling could be spoken of<\/td>\n<\/tr>\n
Solubility<\/th>\ngood in water (zwitterionic form); negligible in non-polar solvents<\/td>\nprepare stock solutions in water or aqueous buffer<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Nomenclature and synonyms<\/h2>\n

A single CAS number, 63-91-2, covers more than a dozen naming variants, some of which are confused with related but distinct substances:<\/p>\n