Assessing the Efficacy of Protease Inactivation for the Preservation of Bioactive Amphibian Skin Peptides.

The skin of amphibians is a rich source of peptides with a wide range of biological activities. They are stored in secretory granules in an inactive form. Upon stimulation, they are secreted together with proteases into the skin.

EThcD as a Unique Tool for the Top-Down De Novo Sequencing of Intact Natural Ranid Amphibian Peptides.

De novo sequencing of any novel peptide/protein is a difficult task. Full sequence coverage, isomeric amino acid residues, inter- and intramolecular S-S bonds, and numerous other post-translational modifications make the investigators employ various chemical modifications, providing a variety of specific fragmentation MS patterns. The chemical processes are time-consuming, and their yields never reach 100%, while the subsequent purification often leads to the loss of minor components of the initial peptide mixture.

Mass Spectrometric De Novo Sequencing of Natural Peptides.

Natural peptides secreted under stress conditions by many organisms are bioactive molecules with a broad spectrum of activities. These molecules could become potential models for novel pharmaceuticals, to which bacteria, according to modern scientific concepts, do not have and cannot develop resistance. Taking this into consideration, it is necessary to clarify the amino acid sequences of such peptides.

Tandem Mass Spectrometry de novo Sequencing of the Skin Defense Peptides of the Central Slovenian Agile Frog .

Peptides released on frogs' skin in a stress situation represent their only weapon against micro-organisms and predators. Every species and even population of frog possesses its own peptidome being appropriate for their habitat. Skin peptides are considered potential pharmaceuticals, while the whole peptidome may be treated as a taxonomic characteristic of each particular population.

EThcD Benefits for the Sequencing Inside Intramolecular Disulfide Cycles of Amphibian Intact Peptides.

Disulfide bonds formed by a pair of cysteine residues in the peptides' backbone represent a certain problem for their sequencing by means of mass spectrometry. As a rule, in proteomics, disulfide bonds should be cleaved before the analysis followed by some sort of chemical derivatization. That step is time-consuming and may lead to losses of minor peptides of the analyzed mixtures due to incomplete reaction, adsorption on the walls of the vials, etc.