Essential components of the xanthophyll cycle differ in high and low toxin Karenia brevis

The Marine Neurotoxin Brevetoxin (PbTx-2) Inhibits Karenia brevis and Mammalian Thioredoxin Reductases by Targeting Different Residues

“…20 Recently reported redox proteomics studies using cysteine reactive tandem mass tags have identified significant differences in the redox status of the proteomes of high and low toxin strains of K. brevis with the high toxin proteome in a more oxidized state. 47 This includes the redox status of Trx, the principal target of TrxR. While our studies demonstrate that PbTx-2 is not a particularly potent inhibitor of KbTrxR, as evidenced by the IC 50 of 56 μM for H 2 O 2 reduction, it is important to keep in mind that the concentration of PbTx-2 in the K. brevis cell can be in the low mM range.…”

“…Low toxin producing K. brevis has been consistently shown to have higher cellular thiol content including a higher level of reduced cysteine in the proteome when compared to a high toxin producing strain . Recently reported redox proteomics studies using cysteine reactive tandem mass tags have identified significant differences in the redox status of the proteomes of high and low toxin strains of K. brevis with the high toxin proteome in a more oxidized state . This includes the redox status of Trx, the principal target of TrxR.…”