Redox interactions of methylene blue with cysteine amino acid as a possible mechanizm of biological action of the dye

Detection of hydrolases of different subclasses in cell-free fractions of Vibrio cholerae O1 and O139 serogroups using radial enzymatic diffusion in agarose gel

“…Thus, the RED is a suitable method for screening cell-free fraction preparations of cholera germ for the presence of hydrolytic enzymes of different subclasses. When using development solutions containing iodine or methylene blue for the detection of alginate lyase and sulfatase activity, the occurrence of artifacts such as the rapid appearance and disappearance of clear zones, their appearance on an agarose gel without a substrate, and their formation with some inert proteins and amino acids (BSA, protamine sulfate, L-cysteine) can be explained by the redox reactions of molecular iodine, which is one of the components of Lugol's solution, and methylene blue with the SH-groups of the proteins contained in the analyzed preparations [7,8]. Oxidation of thiol groups of amino acids cysteine and methionine, glutathione tripeptide, and numerous proteins leads to discoloration of the iodine and methylene blue solutions and, correspondingly, to nonspecific reactions, which can lead to incorrect interpretation of the obtained results (false-positive results).…”

Biophysical investigations of molecular mechanisms of action of chemotherapeutic agents. 2. Antimicrobial and antimalarial agents (Review)

“…Разработанная масс-спектрометрическая методика слежения за редокс-активностью МВ была использована в поисковых исследованиях возможных механизмов вмешательства МВ в процессы, связанные с нейродегенеративной патологией -болезнью Альцгеймера [52]. Было показано, что МВ, восстанавливаясь, способен окислять аминокислотный остаток цистеина в белках, способствуя образованию дисульфидных мостиков [52], препятствуя, тем самым, формированию патологических нейрофибриллярных клубков.…”