Which of the following is not an example of enzyme
catalysed reaction?

Options

A. Hydrogenation of vegetable oils
B. Inversion of cane sugar
C. Conversion of proteins into peptides in intestine
D. Conversion of milk into curd

Answer

To determine which of the following is not an example of an enzyme-catalyzed reaction, we will analyze each option provided:

1. **Hydrogenation of Vegetable Oils**:
- This reaction involves the addition of hydrogen to vegetable oils in the presence of metals such as nickel or platinum. It does not require any enzymes for this process. Therefore, this is not an enzyme-catalyzed reaction.

2. **Inversion of Cane Sugar**:
- This reaction involves the conversion of sucrose (cane sugar) into glucose and fructose. It is catalyzed by the enzyme invertase. Since this reaction involves an enzyme, it is an enzyme-catalyzed reaction.

3. **Conversion of Proteins into Peptides in the Intestine**:
- This process occurs in the digestive system where proteins are broken down into smaller peptides by the action of enzymes such as pepsin. This is also an enzyme-catalyzed reaction.

4. **Conversion of Milk into Curd**:
- The conversion of milk into curd is facilitated by the enzyme produced by Lactobacillus bacteria. This process is also an enzyme-catalyzed reaction.

After analyzing all the options, we conclude that the only reaction that is not catalyzed by an enzyme is the **hydrogenation of vegetable oils**.

### Final Answer:
**The correct answer is: Hydrogenation of vegetable oils.**