An analytical procedure for the determination of trichothecenes in various cereals is described. HPLC was performed with a reversed-phase (C18) column eluted with methanol:water (60:40, v/v). Compounds were detected with a refractive index detector. The elution patterns of free and contaminated samples were compared. The recovery of added T-2 toxin (2 and 5 micrograms/g) in rye and wheat was approximately 80%. The application of this method allows for combined use with other sensitive methods such as mass spectrometry and gas chromatography. The described method is operationally simple, relatively inexpensive, and requires no derivatization.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Purification, subunit structure, and kinetics of the chloroform-released F1ATPase complex from Rhodospirillum rubrum and its comparison with F1ATPase forms isolated by other methods.

A stable and homogeneous adenosine-5'-triphosphatase (ATPase, EC 3.6.1.3) has been solubilized from Rhodospirillum rubrum (R. rubrum) chromatophores by chloroform extraction. Purification of the Ca2+-dependent ATPase activity was 200-fold. Ca2+ can be replaced by Mg2+, Cd2+, and Mn2+. The Km for Ca-ATP (0.17 mM) is increased about 5-fold during solubilization of the enzyme, whereas the Km values for Mg-ATP (0.029 mM) and Cd-ATP (0.014 mM) are not affected. The chloroform-released ATPase has a molecular weight of 400,000 +/- 30,000 and consists of the following subunits (molecular weights in parenthesis): alpha(58,000), beta(53,500), gamma(39,000), delta(18,500), and epsilon(14,000). The amino acid composition and the fluorescence spectra are presented. Besides the chloroform-released ATPase complex three other Ca2+-dependent ATPase forms have been isolated from R. rubrum chromatophores by other methods for comparison. Ultrasonication of the membranes leads to the release of an ATPase complex which is mainly composed of alpha, beta, and gamma-subunits. From an acetone powder extract an ATPase complex could be purified by affinity chromatography which is composed of four kinds of subunits (alpha, beta, gamma, delta). The same acetone powder yields an ATPase consisting of only three different types of subunits (alpha, beta, gamma) if the final purification step is preparative disc electrophoresis on 6% polyacrylamide gels instead of affinity chromatography.

Adenosine Triphosphatases↗

PubMedDate not supplied

3'-Arylazido-beta-alanyl-2-azido ATP, a cross-linking photoaffinity label for F1ATPases.

The synthesis of the 3'-arylazido-2-azido ATP derivative 3'-O-(3-[N-(4-azido-2-nitrophenyl)-amino]propionyl)2-azido-adenosine 5'-triphosphate (2,3'-DiN3ATP) is described. The bifunctional photoreactive ATP analog is characterized spectroscopically. Photoaffinity labeling of F1ATPase from Micrococcus luteus by this analog results in the inactivation of the enzyme and in the formation of higher molecular weight cross-links, composed of alpha- and beta-subunits.

Adenosine Triphosphate↗

PubMedDate not supplied

Chemical and catalytical properties of thermal polymers of amino acids (proteinoids).

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Amino Acid Sequence↗