PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 3444440

[Staphylococcal enterotoxin type D: isolation, purification, identification].

R B Naubet'iarov·M L Beĭlbaeva·Iu V Ezepchuk
View original source ↗Export metadata ↓

Abstract

The three step scheme of isolation and purification of staphylococcal type D enterotoxin was elaborated to obtain the homogeneous protein. The scheme includes protein concentration by (NH4)2SO4 saturation and subsequent fractionation on DEAE-cellulose and Sephacryl S-200. The yield of homogeneous protein is 25.5%. The molecular mass of the 29,600 D protein was identified by electrophoresis in polyacrylamide gel in the presence of SDS. The enterotoxic dose for staphylococcal type D enterotoxin is 5 mkg per kg of body mass as identified in experiments with cats. Immunological identity of the obtained protein was established to the commercial preparation of staphylococcal enterotoxin D produced by "Serva".

Explore related subjects

Chromatography, GelElectrophoresis, DiscEnterotoxinsMolecular WeightStaphylococcus aureusEnglish AbstractJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R B Naubet'iarov, M L Beĭlbaeva, Iu V Ezepchuk. 1987. [Staphylococcal enterotoxin type D: isolation, purification, identification].. https://pubmed.ncbi.nlm.nih.gov/3444440/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1995

DnaX complex of Escherichia coli DNA polymerase III holoenzyme. The chi psi complex functions by increasing the affinity of tau and gamma for delta.delta' to a physiologically relevant range.

An artificial operon that contains tandem holC-holD genes was used to overproduce a complex of the chi and psi subunits of the DNA polymerase III holoenzyme. Normally insoluble by itself, psi forms a tight soluble complex with chi. A purification procedure that yields pure, active chi psi complex in 100-mg quantities suitable for biophysical studies is reported. Sedimentation equilibrium studies demonstrate that chi psi is a 1:1 heterodimer. The presence of chi psi dramatically lowers the level of delta.delta' required to reconstitute holoenzyme to levels expected in vivo. That chi psi accomplishes this by binding to gamma or tau and increasing their affinity for delta.delta' was demonstrated by surface plasmon resonance using a Pharmacia BIA-core instrument. In the absence of delta.delta', chi psi binds to either the gamma or tau DnaX protein with Kd = 2 nM.

Chromatography, Gel↗
PubMed1995

The polypeptide chain of eukaryotic initiation factor 5A occurs in two distinct conformations in the absence of the hypusine modification.

Eukaryotic initiation factor 5A (eIF-5A) requires posttranslational modification of lysine at position 50 to hypusine for its biological activity. We have expressed an unmodified variant of eIF-5A in Escherichia coli and show that it has structural properties different from those of the native protein in terms of its near- and far-UV circular dichroism spectra and its equilibrium unfolding transition with guanidinium chloride. In contrast to the hypusine-modified protein, which unfolds in a two-state process, the complex unfolding transition of unmodified eIF-5A suggests that this variant occurs in two differently folded conformations, F1 and F2. Both conformations are populated under near-physiological conditions at a ration of 60 to 40, respectively. Equilibrium unfolding consists of parallel events: unfolding of F1 to one or several intermediate states (I), and unfolding of F2 to the unfolded state (U). Although the establishment of each of these individual equilibria is fast, the interconversion is slow at guanidinium chloride concentrations between 0 M and 3 M. Kinetic analysis reveals activation energies of 24.3 kcal mol-1 for the reaction of F1 and F2 and 24.1 kcal mol-1 for the reaction of F2 to F1. Both F1 and F2 possess well-defined secondary and tertiary structure. However, the tertiary structures of the two conformations differ as indicated by their distinct near-UV circular dichroism spectra. These differences may be restricted to the C-terminal part of the protein as 2-dimensional 1H-NMR spectra of unmodified eIF-5A reveal no doubled set of proton resonances for aromatic amino acid and histidine residues, of which almost all are located in the N-terminal region.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, Gel↗
PubMed1995

Visible spectrophotometric assay, purification, and molecular properties of a lipoxygenase from eggplant (Solanum melongena Linne) fruits.

We purified a lipoxygenase to homogeneity from eggplant (Solanum melongena Linne) fruits employing the established visible spectrophotometric assay, in which the products of the lipoxygenase-catalyzed reaction, hydroperoxyfatty acids, oxidizes 2,2'-azino-di-[3-ethylbenzothiazoline-(6)-sulfonic acid] diammonium salt in the presence of a catalyst cytochrome c to yield chromophores in the visible region. This allowed for the rapid detection of the lipoxygenase activity and was helpful in accomplishing the efficient purification of the lipoxygenase. The purified lipoxygenase was a monomeric enzyme with a molecular weight of 95,000, s20,w of 5.3 S, and an isoelectric point of 4.4. The specific activity and Km value for the linoleate oxygenation were 7.8 mumol min-1 mg-1 and 0.8 mM, respectively, at 25 degrees C and pH 7.0. The enzyme contained 1.3 g-atom of nonheme iron per enzyme.

Chromatography, Gel↗