RI039, RNase Inhibitor, Human Placenta,I.e. Ribonuclease Prohibitor, Human Placenta is a recombinant expression of human placental RNase inhibitor in Escherichia coli, which can bind to RNase A, RNase B, RNase C, and human placental RNase in a non competitive 1:1 ratio and inhibit their activity, thereby protecting RNA from degradation by these enzymes.