user: ### NOW ANSWER:
Question: What is the abbreviation of the enzyme involved in Carbamoyl phosphate synthetase I deficiency?
Columns: ['Location', 'Abb.', 'Enzyme', 'Disorder', 'Measurements']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Mitochondria', 'NAGS', 'N-Acetylglutamate synthetase', 'N-Acetylglutamate synthase deficiency', '+ Ammonia']
SQL:

assistant: SELECT "Abb." FROM "Table" WHERE "Disorder" = 'Carbamoyl phosphate synthetase I deficiency';