Location of RNase and RNase inhibitor on free cytoplasmic mRNA-protein particles from human placenta

Free cytoplasmic mRNPs were isolated from human placenta. An activity of RNase was associated with these particles but was mostly inhibited by a labile protein inhibitor. Both RNase and RNase inhibitor were extractable from mRNPs by 0.5 M KCl. The nature of the association of the RNase-RNase inhibitor complex with mRNPs makes it suitable as a putative system for control of expression and turnover of mRNPs and therefore of protein synthesis.Abbreviations used RNase ribonuclease - mRNPs messenger ribonucleoprotein particles - pHMB p-hydroxymercuribenzoate