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L‐tyrosine is the precursor of PQQ biosynthesis in Hyphomicrobium X
Author(s) -
van Kleef Mario A.G.,
Duine Johannis A.
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80178-9
Subject(s) - tyrosine , amino acid , phenylalanine , chemistry , biosynthesis , aromatic amino acids , acid hydrolysis , biochemistry , hydrolysis , pyrroloquinoline quinone , stereochemistry , organic chemistry , enzyme , cofactor
A method was developed to study amino acids as possible precursors of PQQ biosynthesis. Cultures of Hyphomicrobium X, growing on [ 13 C]methanol, were supplemented with unlabelled amino acids. Uptake and participation in metabolism were determined via gas chromatography/mass spectrometry of derivatized amino acids, obtained from hydrolysed cellular protein, by measuring their 12 C content. Several amino acids appeared to be incorporated into the protein to a significant extent, without degradation or conversion. Among these were the aromatic amino acids, L‐tyrosine and L‐phenylalanine. Using the same replacement approach, their incorporation into PQQ was determined by 1 H‐ and 13 C‐NMR spectroscopy of purified PQQ obtained from the culture medium. It appeared that the complete carbon skeleton of tyrosine was present, forming the o ‐quinone and pyrrole‐2‐carboxylic acid moieties in PQQ, while phenylalanine was not incorporated at all. Starting with L‐tyrosine, possible biosynthetic routes to PQQ are discussed.