Purification and properties of a ribonuclease from Avena leaf tissues.

摘要: Abstract A ribonuclease was isolated and purified from Avena leaf tissues. The enzyme shown to be an endonuclease which cleaves all the phosphodiester bonds forming nucleoside 2′,3′-cyclic phosphates. As by kinetic analysis, has a preference for secondary phosphate esters of 3′-GMP. early release 2′,3′-GMP followed 2′,3′-AMP 2′,3′-UMP, whereas pronounced lag period proceded releae 2′,3′-CMP. purine/pyrimidine ratio in mixture nucleotides liberated during RNA hydrolysis high at beginning reaction gradually decreased with longer incubation time. relative purine specificity also using homopolymers as substrates. poly U proportion 1:2, known produce maximum interaction, not attacked. hydrolyzed only phosphates considerable extent. following products inhibited enzyme: 3′-AMP, 3′-GMP, 2′,3′-GMP, 3′-CMP, 3′UMP, 2′,3′-CMP 2′,3′-UMP had no or little effect. activity described above found increased rapidly tissue association injury and/or senescence.