US 12,325,872 B2
Method of improving acid decarboxylase activity in vitro under alkaline pH
Howard Chou, Shanghai (CN); Ling Chen, Shanghai (CN); Wenqiang Lu, Shanghai (CN); and Xiucai Liu, Shanghai (CN)
Assigned to CATHAY BIOTECH INC., Shanghai (CN); and CIBT America Inc., Newark, DE (US)
Filed by CATHAY BIOTECH INC., Shanghai (CN); and CIBT America Inc., Newark, DE (US)
Filed on Apr. 13, 2023, as Appl. No. 18/300,251.
Application 18/300,251 is a division of application No. 16/464,104, abandoned, previously published as PCT/CN2016/107083, filed on Nov. 24, 2016.
Prior Publication US 2023/0295602 A1, Sep. 21, 2023
Int. Cl. C12N 9/88 (2006.01); C07K 14/47 (2006.01); C12N 15/70 (2006.01)
CPC C12N 9/88 (2013.01) [C07K 14/47 (2013.01); C12N 15/70 (2013.01); C12Y 401/01018 (2013.01); C07K 2319/00 (2013.01)] 6 Claims
 
1. A method of improving Escherichia coli lysine decarboxylase CadA polypeptide activity by at least 5% in vitro under alkaline pH comprising fusing a prion subunit to the carboxyl terminus of the Escherichia coli lysine decarboxylase CadA polypeptide, wherein the prion subunit has at least 95% identity to the amino acid sequence of the prion subunit region of any one of SEQ ID NOS: 7, 8, 11, 12, 13, 14, 15, 17, or 19, and the Escherichia coli lysine decarboxylase CadA polypeptide has the amino acid sequence of SEQ ID NO: 2 or a biologically active fragment thereof that has lysine decarboxylase CadA polypeptide activity and has at least 95% amino acid sequence identity to SEQ ID NO: 2, and wherein the lysine decarboxylase CadA polypeptide activity is assessed by measuring the production of cadaverine and lysine Produced by a host cell that expresses the lysine decarboxylase cadA polypeptide fused to the prion subunit and a control cell that expresses the acid decarboxylase protein, but is not fused to the prion subunit, under identical conditions.