Razi Journal of Medical Sciences

Ribonuclease inhibitor is an acidic protein, soluble in cytoplasm. It is abundantly present in human placenta. It could be extracted from this organ to the extent of 1mg/placenta using chemical ion exchange and affinity techniques. Molecular weight of this protein is estimated by electophoresis or SDS-PAG electrophoresis using standards of known proteins.

Molecular weight has been found to be 48000D. The inhibitor could from a 1 :1 complex with bovine pancreatic ribpnuclease in a noncompetitive fashion (Ki= 2.9. 10-¹⁰). Optimal PH for such inhibition is found to be 7.6±0.1

This compound is currently for nucleic acid separations due to its protective abilities and also in genetic engineering, to identify genetic defects in a wide variety of diseases. Thus, due to the importance of the subject, we undertook the kinetic - inhibitory studies of this inhibitor to obtain more insight about the regulatory mechanism of the protein.