A cofactor that forms coordination bonds with both substrate and side chains of enzymes is

Options

A. Inorganic cofactors
B. Organic cofactor
C. Vitamins
D. Proteins

Answer

To solve the question about the cofactor that forms coordination bonds with both substrate and side chains of enzymes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Cofactors**:
- Cofactors are non-proteinaceous chemical molecules that assist enzymes in biochemical reactions. They can be either inorganic or organic.

2. **Analyze the Options**:
- The options provided are inorganic cofactors, organic cofactors, vitamins, and proteins.

3. **Eliminate Proteins**:
- Since cofactors are defined as non-proteinaceous, we can eliminate proteins as a possible answer.

4. **Evaluate Vitamins**:
- Vitamins are generally larger, bulky compounds and do not typically form coordination bonds with substrates or enzyme side chains. Therefore, we can eliminate vitamins as well.

5. **Distinguish Between Inorganic and Organic Cofactors**:
- Inorganic cofactors are usually metallic ions that can form coordination bonds with both substrates and enzyme side chains.
- Organic cofactors, on the other hand, are typically larger molecules and do not form such bonds.

6. **Conclude the Correct Answer**:
- Since inorganic cofactors (metal ions) can form coordination bonds with both substrates and side chains of enzymes, the correct answer is **inorganic cofactors**.

### Final Answer:
The cofactor that forms coordination bonds with both substrate and side chains of enzymes is **inorganic cofactors**.