Correct statement about non competitive inhibitor

Options

A. Structurally similar to substrate
B. Changes structure of enzymes
C. Binds to active site
D. Promote catalysis after binding to enzyme

Answer

### Step-by-Step Solution:

1. **Understanding Non-Competitive Inhibitors**:
Non-competitive inhibitors are a type of enzyme inhibitor that bind to an enzyme at a site other than the active site. This binding does not prevent the substrate from binding to the active site, but it does inhibit the enzyme's activity.

2. **Analyzing the Options**:
We need to evaluate each of the provided options to determine which statement is correct regarding non-competitive inhibitors.

- **Option 1**: "Structurally similar to substrate" - This is incorrect. Non-competitive inhibitors do not have to be structurally similar to the substrate.

- **Option 2**: "Changes structure of the enzymes" - This is correct. Non-competitive inhibitors bind to an allosteric site and induce a conformational change in the enzyme, altering its structure.

- **Option 3**: "Binds to the active site" - This is incorrect. Non-competitive inhibitors do not bind to the active site; they bind to a different site on the enzyme.

- **Option 4**: "Promotes catalysis after binding to the enzyme" - This is incorrect. Non-competitive inhibitors inhibit the enzyme's activity rather than promoting catalysis.

3. **Conclusion**:
After analyzing the options, the correct statement about non-competitive inhibitors is: **"Changes structure of the enzymes" (Option 2)**. This is because non-competitive inhibitors bind to an allosteric site, causing a conformational change that affects the enzyme's function.