What is the abbreviation of the enzyme involved in carbamoyl phosphate synthetase i deficiency?
CREATE TABLE "the_six_urea_cycle_disorders" (
  "location" text,
  "abb" text,
  "enzyme" text,
  "disorder" text,
  "measurements" text
);
SELECT "abb" FROM "the_six_urea_cycle_disorders" WHERE "disorder"='carbamoyl phosphate synthetase i deficiency';