Thiol groups succinate dehydrogenase

Mercury interferes with mitochondrial oxidation in the brain through mercaptide formation with thiol groups in pyruvate oxidase. Succinic dehydrogenase of the citric acid cycle is also inhibited. 

Lewisite shares many biochemical mechanisms of injury with the other arsenical compounds. It inhibits many enzymes in particular, those with thiol groups, such as pyruvic oxidase, alcohol dehydrogenase, succinic oxidase, hexokinase, and succinic dehydrogenase. As is tme with mustard, the exact mechanism by which Lewisite damages cells has not been completely defined. Inactivation of carbohydrate metabolism, primarily because of inhibition of the pymvate dehydrogenase complex, is thought to be a key factor (Trammel, 1992). 

Glucose esters of 3-N. (endecaphyllins) are responsible for the toxicity of Indigofera endecaphylla for grazing animals. 3-N. functions as suicide substrate of succinate dehydrogenase where the formed 3-nitro-acrylic acid adds to the active thiol group of the enzyme. The compound is formed biosynthetically in Penicillium atrovenetum from L-aspartic acid which is oxidized to the a-nitrosuccinate and then decarboxy-lated to furnish the aci-nitro form of 3-N.. Malonate and N-hydroxymalonamate appear to be intermediates in Indigofera spicata. 

The literature confirms that attempts to clarify the mechanism of silver nanoparticle action against bacteria, viruses, and fungi have been taken. One of the most common mechanisms of nanosilver antibacterial activity is based on its natural affinity for bonding with a thiol group present in cysteine, which is a protein building material of bacterial cell walls. Consequently, the enzymatic function of the proteins is disturbed and the cellular respiration chain is interrupted. At the same time other enzymes such as NADH and succinate dehydrogenase are destroyed (Park et al., 2009). 

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