33784-54-2Relevant articles and documents
Role of protecting groups in the preparation of thiolate complexes of Technetium-99 m using cysteine as a model
Roy,Debnath, M. Chatterjee,Sanyal, Kasturi,Das,Banerjee
, p. 835 - 847 (2006)
An attempt has been made to develop a suitable protecting group for the thiolate function for 99mTc binding ligands having such function and which could be deprotected automatically during 99mTc-chelation without the use of any additional reagents. As a model ligand a simple molecule like L-cysteine was selected. Seven S-protected derivatives of this amino acid were synthesized, radiolabelled with technetium-99 m under a variety of experimental conditions and the yield of the desired chelate was compared to that of 99mTc-L-cysteine, the authentic standard chelate, by HPLC. The corresponding 99Tc chelate of cysteine from L-cystine and S-thiomethyl L- cysteine was also prepared. It was found that the 99Tc chelates exhibited similar retention profiles to those of the corresponding 99mTc chelates in reverse phase HPLC. The results of the biodistribution studies after 99mTc chelation were likewise compared to those of 99mTc-L-cysteine. The effect of probenecid on renal excretion was studied only on the 99mTc chelate of S-thiomethyl-L- cysteine to determine whether tubular excretion was involved. The results suggest that the S-thiomethyl group could be used as an ideal protective group to mask the high reactivity of thiolate functions attached to different 99mTc binding ligands. Copyright
Characterisation of the l-Cystine β-Lyase PatB from Phaeobacter inhibens: An Enzyme Involved in the Biosynthesis of the Marine Antibiotic Tropodithietic Acid
Dickschat, Jeroen S.,Rinkel, Jan,Klapschinski, Tim,Petersen, J?rn
, p. 2260 - 2267 (2017/10/25)
The l-cystine β-lyase from Phaeobacter inhibens is involved in the biosynthesis of the sulfur-containing antibiotic tropodithietic acid. The recombinant enzyme was obtained by heterologous expression in Escherichia coli and biochemically characterised by unambiguous chemical identification of the products formed from the substrate l-cystine, investigation of the substrate spectrum, determination of the enzyme kinetics, sequence alignment with closely related homologues and site-directed mutagenesis to identify a highly conserved lysine residue that is critical for functionality. PatB from P. inhibens is a new member of the small group of characterised l-cystine β-lyases and the first example of an enzyme with such an activity that is required for the biosynthesis of an antibiotic. A comparison of PatB to previously reported enzymes with l-cystine β-lyase activity from bacteria and plants is given.
Cysteine and glutathione mixed-disulfide conjugates of thiosulfinates: Chemical synthesis and biological activities
Zhang, Guodong,Ll, Bln,Lee, Chen-Hsien,Parkin, Klrk L.
experimental part, p. 1564 - 1571 (2010/09/09)
The chemical syntheses of cysteine (CYS) and glutathione (GSH) mixed -disulfide conjugates (CySSR, GSSR, respectively) of mercapto residues representing most of the R groups of thiosulfinates (R = methyl, ethyl, propyl, and allyl) are described. Gram-scale conjugates were prepared as >98% pure preparations, with 80% reaction yield for each of the two seminal synthesis steps, with structures confirmed by 1H NMR and high-resolution MS analyses. These conjugates are derivatives of thiosulfinates that may be evolved in processed foods, in the digestive tract, and through in vivo metabolism. The prepared conjugates were found to be able to induce quinone reductase (QR, a representative phase II enzyme) in murine hepatoma cells (Hepa 1c1c7) and to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated macrophage cells (RAW 264.7), indicating they have potential cancer preventive and anti-inflammatory activities. Among the prepared conjugates, the allyl conjugates of CYS and GSH, S-allylmercaptocysteine (CySSA) and S-allylmercaptoglutathione (GSSA), showed the most potent activity regarding QR induction and NO production inhibition. The conjugates with saturated R groups were also active and conferred biological activity as cystine and oxidized glutathione exhibited no effects in these cellular assays.
