Isoelectric focusing of ureases from Campylobacter pylori and related organisms

Abstract

Agarosé gel isoelectric focusing was used to determine the isoelectric points of ureases from strains of gastric campylobacterlike organisms isolated from ferrets (pI 5.4), baboons (pI 5.7), and pigs (pI 5.9) and from isolates of Carpylobacterpylori in humans (pI 5.9). This technique may help differentiate these closely related bacteria.

Purification and characterization of the urease enzymes of Helicobacter species from humans and animals

“…More recently, Evans et al (13) found that the enzyme from H. pylon has a pI of 5.93. No differences in the pl values of ureases from the different species were observed in our study, in contrast to Tompkins et al (54). At the time of that publication, the taxonomic identification of the animal isolates was uncertain, and they had not yet been classified as H. pylon.…”

“…The pl of 6.1 noted for active urease is close to the values reported elsewhere. Tompkins et al (54), using agarose isoelectric focusing, reported urease pI values of 5.9 for H. pylon for a human and a pig isolate, 5.7 for a baboon H. pylon isolate, and 5.4 for H. mustelae. Dunn et al (9) reported the native enzyme to have a pI of 5.99 ± 0.03.…”

“…Samples of Helicobacter urease were prepared for use in nondenaturing isoelectric focusing gels by the freeze-thaw method outlined by Tompkins et al (54). Briefly, 3-day cultures from blood agar plates were harvested into doubledistilled deionized water and then lysed by four cycles of freezing (in liquid nitrogen) and thawing (in a 40°C water bath).…”

“…Urease activity was detected in PAGE gels either by the urease-specific silver stain (7) or by a pH-dependent staining method (14), except that cresol red (0.1%, wt/vol) was used in place of phenol red. Activity within PAGIF gels was detected as described by Tompkins et al (54). With the cresol red activity stain, bands of urease activity were detected by flooding the gel with 2% (wt/vol) urea.…”