Enzymatic characterization of 30 kDa lipase from Pseudomonas aeruginosa ATCC 27853.

An extracellular lipase from Pseudomonas aeruginosa ATCC 27853 has been purified and its enzymatic characteristics were determined. According to SDS-PAGE and gel filtration molecular mass estimated to be 30 kDa, what classified the lipase in group I.1. Although 14 lipases from P. aeruginosa with similar molecular mass are referred to date, their basic enzymatic properties have not been reported yet. To address the gap we found: the optimal temperature and pH in water solution being 50 degrees C and 9.3, respectively; the lipase was inhibited with Hg2+ ions and sodium dodecylsulphate (SDS), while non-ionic detergent Triton X-100 activated the enzyme; the lipase hydrolyzed more rapidly middle chain triglycerides and it was not regiospecific; the lipase demonstrated naturally occurring stability in different organic solvents with concentrations ranging from 30 to 70%, including good thermal stability in 30% organic solvent solution. Even though strain P. aeruginosa ATCC 27853 was not isolated from extreme environment it showed activity in organic solvent suggesting that this lipase is suitable for variety of applications, including reactions in water restricted medium and bioremediation of contaminations by organic solvents.

Detection of gelatinase B activity in serum of gastric cancer patients.

AIM: To determine the proteolytic activity and expression of gelatinase B in serum of gastric cancer patients and their correlation with the stage of the tumor. METHODS: Sera from 23 patients who underwent surgery for primary gastric cancer as the experimental group and from 11 as the control group were used to determine the proteolytic activity and its inhibition by EDTA and 1,10-phenanthroline. Gelatinase B activity was detected by SDS polyacrylamide gel electrophoresis (SDS-PAGE) and SDS-PAGE zymography. RESULTS: Proteolytic enzyme activity was increased in gastric cancer patients when compared to the control group (P < 0.05). The proteinases were determined to be metalloproteinases upon inhibition test with specific metalloproteinase inhibitors 1,10-phenanthroline (P < 0.05) and EDTA (P < 0.01). SDS-PAGE and SDS-PAGE zymography revealed gelatinase B (proMMP-9) activity and its molecular mass of 92 ku. CONCLUSION: Proteinase activity is overexpressed in serum of gastric cancer patients. Gelatinase B in serum plays an important role in the progression of gastric cancer. ProMMP-9 can be used as a marker for invasiveness of gastric cancer.