| 摘要 |
A gram-negative bacterial cell is described that is deficient in a chromosom al gene present in a wild~-type such cell which gene shares at least 80% sequen ce identity with the native sequence of the yfcK gene and encodes an aminopeptidase. Alternatively, a gram-negative bacterial cell is deficient i n a chromosomal gene present in a wild-type such cell which gene encodes an aminopeptidase that shares at least 80% sequence identity with the native sequence of aminopeptidase b2324. Either of these types of cells, when 10 comprising a nucleic acid encoding a heterologous polypeptide, produces an N - terminal unclipped polypeptide when it is cultured and the polypeptide recovered, with virtually no N-terminal clipped polypeptide produced as an impurity. Conversely, a method is provided for cleaving an N-terminal amino acid from a polypeptide comprising contacting the polypeptide with an aminopeptidase sharing at least 80% sequence identity with the native sequen ce of aminopeptidase b2324. |
