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What is the role of ATCase? Explain how it performs this role. - VCE - SSCE Biology - Question 1 - 2014 - Paper 1
Question 1
What is the role of ATCase? Explain how it performs this role.
Worked Solution & Example Answer:What is the role of ATCase? Explain how it performs this role. - VCE - SSCE Biology - Question 1 - 2014 - Paper 1
Step 1
Role of ATCase
Answer
ATCase, or aspartate transcarbamoylase, plays a crucial role in the regulation of pyrimidine biosynthesis, specifically in the initial step of synthesizing CTP from aspartate and a common substrate. It acts as a regulatory enzyme that adjusts the flow of metabolites through this pathway, responding to the cellular levels of nucleotides. This regulation ensures a balance in the nucleotide pool, crucial for adequate RNA synthesis.
Step 2
How ATCase Performs Its Role
Answer
ATCase performs its role through allosteric regulation. When the cell has high levels of CTP, it binds to the allosteric site on ATCase, resulting in a conformational change that decreases the enzyme's activity. Conversely, when CTP levels are low, the enzyme is activated, allowing for increased synthesis of CTP from aspartate and carbamoyl phosphate. This mechanism helps in fine-tuning the production of nucleotides according to the cellular requirements.