The enzyme ADA, that is crucial for the immune system to function is abbreviated as :

Options

A. Adenosine deoxyaminase
B. Adenosine deaminase
C. Aspartate deaminase
D. Arginine deaminase

Answer

To solve the question about the enzyme ADA that is crucial for the immune system, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Enzyme**: The question asks for the abbreviation of the enzyme ADA, which is crucial for the immune system.

2. **Understand the Role of ADA**: ADA stands for an enzyme that is involved in the immune system. It is important to know that a deficiency in this enzyme leads to a genetic disorder.

3. **Recognize the Genetic Disorder**: The deficiency of ADA causes a condition known as Severe Combined Immunodeficiency (SCID). This highlights the importance of ADA in immune function.

4. **Define ADA**: The full name of ADA is Adenosine Deaminase. This enzyme plays a critical role in the metabolism of nucleotides.

5. **Explain the Function of Adenosine Deaminase**: Adenosine Deaminase (ADA) is responsible for converting deoxyadenosine into deoxyinosine. This process is crucial because the accumulation of deoxyadenosine can be toxic to lymphocytes, which are essential for the immune response.

6. **Conclude with the Answer**: Based on the information gathered, the enzyme ADA is abbreviated as Adenosine Deaminase.

### Final Answer:
The enzyme ADA, that is crucial for the immune system to function, is abbreviated as **Adenosine Deaminase**.

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