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The N-terminal cysteine of human asparagine synthetase is essential for glutamine-dependent activity

1989; Elsevier BV; Volume: 264; Issue: 33 Linguagem: Inglês

10.1016/s0021-9258(19)47138-x

1083-351X

Gino Van Heeke, S M Schuster,

Polyamine Metabolism and Applications

Site-specific mutagenesis was used to replace the N-terminal cysteine in human asparagine synthetase by an alanine. The mutant enzyme was expressed in the yeast Saccharomyces cerevisiae, and the asparagine synthetase activity was analyzed in vitro. The mutation resulted in the loss of the glutamine-dependent asparagine synthetase activity, while the ammonia-dependent activity remained unaffected. These results confirm the existence of a glutamine amidotransfer domain with an N-terminal cysteine essential for the glutamine-dependent asparagine synthetase activity.