Concept:Certain external chemicals can act as severe, irreversible poisons to biological systems by violently attacking the fragile tertiary structure of proteins.
Solution:- Heavy metal ions (such as Mercury \( \text{Hg}^{2+} \), Lead \( \text{Pb}^{2+} \), and Silver \( \text{Ag}^+ \)) are highly toxic inhibitors.
- They forcefully bind to the reactive sulfhydryl (-SH) groups of the amino acid cysteine within the enzyme.
- This physically breaks the crucial disulfide bridges that hold the enzyme together, causing catastrophic and irreversible denaturation.
Why other options are incorrect:Methane and noble gases are largely inert in biological systems and do not break protein bonds. Mutase is a class of isomerase enzymes, not an inhibitor.
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