Glutamate-1-semialdehyde aminotransferase from Sulfolobus solfataricus

Gianna Palmieri, Michela Di Palo, Andrea Scaloni, Stefania Orrù, Gennaro Marino, Giovanni Sannia

Research output: Contribution to journalArticlepeer-review

Abstract

Glutamate-1-semialdehyde aminotransferase (GSA-AT) from the extremely thermophilic bacterium Sulfolobus solfataricus has been purified to homogeneity and characterized. GSA-AT is the last enzyme in the C5 pathway for the conversion of glutamate into the tetrapyrrole precursor δ-aminolaevulinate (ALA) in plants, algae and several bacteria. The active form of GSA-AT from S. solfataricus seems to be a homodimer with a molecular mass of 87 kDa. The absorption spectrum of the purified aminotransferase is indicative of the presence of pyridoxamine 5′-phosphate (PMP) cofactor, and the catalytic activity of the enzyme is further stimulated by addition of PMP. 3-Amino-2,3-dihydrobenzoic acid is an inhibitor of the aminotransferase activity. The N-terminal amino acid sequence of GSA-AT from S. solfataricus was found to share significant similarity with the eukaryotic and eubacterial enzymes. Evidence is provided that ALA synthesis in S. solfataricus follows the C5 pathway characteristic of plants, algae, cyanobacteria and many other bacteria.

Original languageEnglish
Pages (from-to)541-545
Number of pages5
JournalBiochemical Journal
Volume320
Issue number2
Publication statusPublished - Dec 1 1996

ASJC Scopus subject areas

  • Biochemistry

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