Phenylalanine 4-monooxygenase : the "sulfoxidation polymorphism"

1. Consistent differences in the proportion of an orally administered dose of S-carboxymethyl-l-cysteine subsequently excreted in the urine as S-oxide metabolites were reported 40 years ago. This observation suggested the existence of inter-individual variation in the ability to undertake the enzymatic S-oxygenation of this compound. Pedigree studies and investigations employing twin pairs indicated a genetically controlled phenomenon overlaid with environmental influences. It was reproducible and not related to gender or age.2. Studies undertaken in several healthy volunteer cohorts always provided similar results that were not significantly different when statistically analysed. However, when compared to these healthy populations, a preponderance of subjects exhibiting the characteristic of poor sulfoxidation of S-carboxymethyl-l-cysteine was found within groups of patients suffering from various disease conditions. The most striking of these associations were witnessed amongst subjects diagnosed with neurodegenerative disorders; although, underlying mechanisms were unknown.3. Exhaustive investigation has identified the enzyme responsible for this S-oxygenation reaction as the tetrahydrobiopterin-dependent aromatic amino acid hydroxylase, phenylalanine 4-monooxygenase classically assigned the sole function of converting phenylalanine to tyrosine. The underlying principle is discussed that enzymes traditionally associated solely with intermediary metabolism may have as yet unrecognised alternative roles in protecting the organism from potential toxic assault.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:50

Enthalten in:

Xenobiotica; the fate of foreign compounds in biological systems - 50(2020), 1 vom: 10. Jan., Seite 51-63

Sprache:

Englisch

Beteiligte Personen:

Mitchell, Stephen C [VerfasserIn]
Steventon, Glyn B [VerfasserIn]

Links:

Volltext

Themen:

1D1Y95PXXA
47E5O17Y3R
740J2QX53R
Carbocysteine
Carbocysteine-lysine
EC 1.14.16.1
Journal Article
Phenotype
Phenylalanine
Phenylalanine 4-monooxygenase
Phenylalanine Hydroxylase
Phenylalanine hydroxylase
Review
S-carboxymethyl-l-cysteine
Sulfoxidation

Anmerkungen:

Date Completed 20.02.2020

Date Revised 20.02.2020

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1080/00498254.2019.1636419

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM298475332