Human placental ribonuclease inhibitor is an acidic protein of about 50kDa with an amino acid composition characterized by unusually high contents of leucine and cysteine.

• 人胎盘核糖核酸酶抑制因子(Human Ribonuclease Inhibitor, HRI)是一种存在于细胞浆中的50 kDa的酸性蛋白质,富含亮氨酸和半胱氨酸。