[Expression of a human ribonuclease inhibitor variant in Escherichia coli and silkworm insect cell (Bombyx mori)].

Abstract

Ribonuclease inhibitor (RI) is an acidic 50 kD protein with a high content of leucine and cysteine residues. RI inhibits RNases of the pancreatic type. A variant of RI was cloned from human fetal liver cDNA library by polymerase chain reaction (PCR). Compared with the reported RI, only two variations Arg(359)Ala and Leu(365)Pro were found in RIv amino acid sequence. Recombinant RIv has been expressed both in Escherichia coli and silkworm insect cells (Bombyx mori). The recombinant RIv exhibited inhibition activity on ribonucleolytic activity of RNase A in vitro system.