Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the abbreviation of the enzyme involved in carbamoyl phosphate synthetase i deficiency?

### Inputs:
table_name: table, columns: ['Location', 'Abb.', 'Enzyme', 'Disorder', 'Measurements']

### Response:
SELECT Abb. FROM table WHERE Disorder = carbamoyl phosphate synthetase i deficiency