For ABO system of blood group in humans, allele IA produces ______ enzyme.

Options

A. N- acetylgalactosamine transferase
B. Glactosyl transferase
C. N- muramic transferase
D. NAG & NAM

Answer

To solve the question regarding the ABO system of blood groups in humans and the enzyme produced by allele IA, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the ABO Blood Group System**:
- The ABO blood group system is determined by the presence of specific antigens on the surface of red blood cells (RBCs). These antigens are controlled by the I gene.

2. **Identify the Alleles**:
- The I gene has three alleles: IA, IB, and i.
- IA and IB are dominant alleles, while i is a recessive allele.

3. **Function of Allele IA**:
- The allele IA is responsible for producing a specific enzyme that contributes to the formation of the A antigen on the RBCs.

4. **Determine the Enzyme Produced by IA**:
- The enzyme produced by the IA allele is known as N-acetylgalactosamine transferase (also referred to as A-transferase). This enzyme is crucial for the synthesis of the A antigen.

5. **Role of N-acetylgalactosamine Transferase**:
- This enzyme transfers N-acetylgalactosamine (GalNAc) from a donor molecule (uridine diphosphate GalNAc) to the H antigen, converting it into the A antigen.

6. **Conclusion**:
- Therefore, the correct answer to the question is that allele IA produces the enzyme N-acetylgalactosamine transferase.

### Final Answer:
**N-acetylgalactosamine transferase**