25779-79-7Relevant academic research and scientific papers
Characterization of the disulfides of bio-thiols by electrospray ionization and triple-quadrupole tandem mass spectrometry
Rubino, Federico Maria,Verduci, Cinzia,Giampiccolo, Rosario,Pulvirenti, Salvatore,Brambilla, Gabri,Colombi, Antonio
, p. 1408 - 1416 (2007/10/03)
Glutathione and other intracellular low molecular mass thiols act both as the major endogenous antioxidant and redox buffer system and, as recently highlighted, as an important regulator of cellular homeostasis. Such cellular functions are mediated by protein thiolation, a newly recognized post-translational modification which involves the formation of mixed disulfides between GSH and key disulfide-linked Cys residues in the native protein structure. It is also well known that thiol-seeking heavy metals, such as mercury, cadmium and lead, may interfere in this regulatory system, thus disrupting the cellular functioning. To identify such mixed disulfides in order to investigate their biological role, 15 homo- and heterodimeric disulfides were prepared by air oxidation of binary mixtures containing cysteine, homocysteine, penicillamine, N-acetylcysteine, N-acetylpenicillamine and glutathione and their protonated molecules were characterized by mass spectrometry. Collisionally activated unimolecular decomposition of protonated homo- and heterodimeric disulfides generated by electrospray ionization gives rise to fission of the disulfide system both between the two sulfur atoms and across the C-S bonds, to yield structurally specific fragments which allow one to define the structure of the compounds and to discriminate between isomeric compounds. Fission between the sulfur atoms yields a pair of R-S? ions and, in some cases, also the complementary fragments corresponding to the protonated amino acids. Fission across the C-S bonds mainly occurs in the disulfides of N-acetylcysteine and N-acetylpenicillamine and gives rise to non-S-containing fragments formally similar to those obtained from some mercapturic acids. The complementary fragments, formally connected as R-S-S+ ions are also observed. Fragmentation of glutathione disulfides mainly shows the characteristic loss of the terminal γ-linked glutamic acid and little, if any, fragmentation of the disulfide system. Copyright
Cosmetic composition
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, (2008/06/13)
A composition suitable for topical application to mammalian skin and hair for inducing, maintaining or increasing hair growth comprises a hair growth promoter chosen from glutamine derivatives and salts thereof. The composition preferably also comprises an activity enhancer which may be chosen from hair growth stimulants, penetration enhancers and cationic polymers.
Cosmetic composition containing DOPA derivatives
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, (2008/06/13)
A composition for topical application to human hair or skin contains a chemical analogue of dihydroxyphenyl alanine (DOPA). This chemical analogue can be absorbed by skin or by a hair follicle and metabolised in-vivo, thus leading to the formation of melanin in skin or to the growth of melanin-pigmented hair. Consequently the composition can give controlled skin darkening to mimic sun-induced tanning or can bring about the growth of dar hair in place of the grey or white hair.
Cosmestic composition
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, (2008/06/13)
A composition suitable for topical application to mammalian skin and hair for inducing, maintaining or increasing hair growth comprises a hair growth promoter chosen from glutamic acid derivatives and salts thereof. The composition preferably also comprises an activity enhancer which may be chosen from hair growth stimulants, penetration enhancers and cationic polymers.
