The effect of starvation stress on Lactobacillus brevis L62 protein profile determined by de novo sequencing in positive and negative mass spectrometry ion mode.

Rationale: We describe a novel negative chemically activated fragmentation/positive chemically activated fragmentation (CAF-/CAF+) technique for protein identification. The technique was used to investigate Lactobacillus brevis adaptation to nutrient deprivation.

Methods: The CAF-/CAF+ method enables de novo sequencing of derivate peptides with negative and positive ion mode matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry (MS/MS).

A product of ozonolysis of cholesterol alters the biophysical properties of phosphatidylethanolamine membranes.

There is evidence that some products of the reaction of ozone with cholesterol contribute to atherosclerosis. One of these compounds is 3beta-hydroxy-5-oxo-5,6-secocholestan-6-al. We have synthesized this compound and have demonstrated that it reacts with phosphatidylethanolamine to form a Schiff base.