Purification and properties of a histidine decarboxylase from Staphylococcus epidermidis TYH1 isolated from Japanese fish-miso

• Published in: Fisheries science 2014-01, Vol.80 (1), p.93-101
• Main Authors: Furutani, Ayumi, Harada, Yasuyuki, Shozen, Kei-ichi, Yokoi, Ken-ji, Saito, Masataka, Satomi, Masataka
• Format: Article
• Language: English
• Subjects: Staphylococcus; Staphylococcus epidermidis
• ISSN: 0919-9268; 1444-2906
• DOI: 10.1007/s12562-013-0675-9

Histidine decarboxylase (HDC) from Staphylococcus epidermidis TYH1, a halotolerant histamine-producing bacterium isolated from Japanese fermented fish-miso, was purified to homogeneity for the first time. The enzyme was purified 182-fold from cell-free extracts by ammonium sulfate precipitation, anion exchange chromatography and gel filtration chromatography. The N-terminal amino acid sequences of two polypeptide chains of 27-30 and 7-9 kDa were highly homologous with those of alpha - and beta -chains of other staphylococcal HDCs. The optimum pH and temperature for the enzyme were 6.0 and 60 degree C, respectively. This enzyme did not decarboxylate lysine, arginine, tyrosine, tryptophan or ornithine. The enzyme activity decreased with the addition of NaCl. At pH 4.8, the V sub(max) and K sub(m) values were 45.5 mu mol histamine min super(-1) mg super(-1) and 1.10 mmol/L, respectively. Moreover, this enzyme was resistant to heat treatment (80 degree C for 15 min) and was stable upon freezing at -30 degree C for 7 days. The very similar physiological properties of this enzyme and the almost identical N-terminal amino acid sequence to that of the HDC from S. capitis indicated that this enzyme may be evolutionally highly conserved in the genus Staphylococcus. The biophysical properties of staphylococcal HDC were elucidated using native purified enzyme.