Tags: Protein.
Ribonuclease inhibitor (RI) is a large (~450 residues ~49 kDa) acidic (pI ~4.7) leucine-rich repeat protein that forms extremely tight complexes with certain ribonucleases. It is a major cellular protein comprising ~0.1% of all cellular protein by weight and appears to play an important role in regulating the lifetime of RNA.RI has a surprisingly high cysteine content (~6.5% cf. 1.7% in typical proteins) and is sensitive to oxidation.
