Purification and properties of a proteinase from a marine luminous bacterium, Vibrio harveyi strain FLA-11.

Abstract

A proteolytic, marine luminous bacterium was isolated from seawater and identified as Vibrio harveyi strain FLA-1 1. A proteinase from this strain, with a specific activity 61-fold higher than that of the culture supernatant, was purified to homogeneity. The purified enzyme had a molecular weight of 84,000, comprising a tetramer of 21,000 molecular weight subunits. The enzyme was most active at pH 8.0 and 55°C, and stable below 40°C. The enzyme activity was completely inhibited by EDTA, orthophenanthrolin and phosphoramidon. Metal ions such as Cu2+, Hg2+, Ni2+, Cd2+ and Co2+also inhibited the activity. These results indicate that this enzyme is a metal-chelatersensitive, alkaline proteinase.

Pathogenicity of Vibrio harveyi to salmonids

“…However, proteases and haemolysin activity in the ECP are certainly involved in the pathogenesis of some isolates. As such, the present study reinforces previous investigations about proteases of V. harveyi ( Fukasawa, Nakamura, Kamii, Ohyama & Osumi 1988a; Fukasawa, Nakamura, Miyahira & Kurata 1988b; Liu et al . 1997 ), although the pivotal role of these enzymes in pathogenesis is not confirmed.…”

Isolation and characterization of pathogeny from cultured banded grouper

“…Liu et al [12] purified and studied an extracellular protease produced by pathogenic V. harvey and reported it was the first cysteine protease found in Vibrio species. These results had some differences from previous studies of the protease from V. harveyi [13] . Conclusions about pathogenicity of V. harveyi haven't been determined by now and further researches should be carried out.…”

Characterization of extracellular products from an isolate of Vibrio harveyi recovered from diseased post‐larval Penaeus vannamei (Bonne)

“…However, it is possible that a number of the lower molecular weight bands represented breakdown products of the higher molecular weight proteases. Certainly, protease production by V. harveyi has been investigated previously, with Fukasawa, Nakamura, Kamii, Ohyama & Osumi (1988a) and Fukasawa, Nakamura, Miyahira & Kurata (1988b) reporting the presence of three metal chelator sensitive proteases in ECPs produced from environmental (water) isolates of V. harveyi with molecular weights of 84, 49 and 46 (= dimer of two, 23 kDa). In addition, Liu et al .…”