Description_x000D_ Biochem/physiol Actions_x000D_ Angiogenin, a liver-derived angiogenic factor, is a single chain polypeptide with an isoelectric point of pl >9.5 and a member of the ribonuclease superfamily. Although the ribonucleolytic activity of angiogenin toward most RNase A substrates is lower than that of RNase A, this activity is essential to its angiogenic activity since inhibition of the angiogenin RNase activity will inhibit the angiogenic activity. High affinity receptors for angiogenin are expressed in cultured aortic smooth muscle cells and can be modulated by protamin, heparin and placental ribonuclease inhibitor._x000D_ Angiogenin, a liver-derived angiogenic factor, is a single chain polypeptide with an isoelectric point of pl >9.5 and a member of the ribonuclease superfamily._x000D_ Physical form_x000D_ Lyophilized from a 0.2 μm filtered solution in phosphate buffered saline containing 2.5 mg bovine serum albumin._x000D_ Analysis Note_x000D_ The activity of human angiogenin is tested in culture by measuring its ribonucleolytic activity for yeast tRNA.