Histidine-Decarboxylase Activity of Leuconostoc-Oenos-9204

ROLLAN, GC; COTON, E; LONVAUDFUNEL, A

FOOD MICROBIOLOGY

Elsevier Science Ltd

Año: 1995 vol. 12 p. 455 - 461

Some bacteria are able to produce histamine from histidine via an enzyme: histidine decarboxylase (HDC). This biogenic amine may be responsible for vasomotor and digestive disturbances. In food such as fish meat or fermented products such as sauerkraut, cheese, fermented sausages and wines, bacteria can produce histamine. Recently, Lonvaud-Funel and Joyeux isolated a strain of Leuconostoc oenos (Leuc. oenos 9204), which is the species mainly responsible for malolactic fermentation in wines. We have studied the enzymatic activity on cell suspensions and cell-free extracts. At pH optimum 4·8, the HDC activity exhibited a Michaelis-Menten kinetic (Km=0·34 mmol l−1, Vmax=89·35 nmol/min/mg), while at pH 7·6 a sigmoidal kinetic was observed. Histamine competitively inhibited the enzymatic activity with a Ki value of 50 mm. The effects of different compounds encountered in wines were also investigated. A high ethanol concentration (12%) reduced the enzymatic activity of cell suspensions and did not affect the activity of the cell-free extract. l-lactic acid and citric acid inhibited both, whole cells and cell-free extract.