Purification and characterization of a ribonuclease from the wild edible mushroom <i>Armillaria luteo-virens</i>

Abstract

A 15 kDa ribonuclease (RNase) was purified from dried fruiting bodies of the wild edible mushroom

<i>Armillaria luteo-virens</i>. The simple 4-step purification protocol involved ion-exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on SP-Sepharose and a final gel filtration by FPLC on Superdex-75. The RNase was unadsorbed on Affi-gel blue gel, but adsorbed on DEAE-cellulose and SP-Sepharose. The N-terminal amino acid sequence of purified RNase was AGVQYKLTILLV, which <span style="mso-bidi-font-style:italic">showed low <span style="mso-fareast-font-family:SimSun;mso-fareast-language:ZH-CN; mso-bidi-font-style:italic" lang="EN-GB">sequence homology to those of previously reported RNases. The optimal pH and temperature of the enzyme were very close to<span style="mso-bidi-font-style:italic"> 4.0 and 70°C, respectively. The enzyme showed considerably high ribonucleolytic activity and broad specificity towards polyhomoribonucleotides, with a specificity of poly(U)>poly(C)>poly (G)>poly(A). The ribonucleolytic activities towards poly(U), poly(C), poly(G) and poly(A) were 279.5, 184.1, 69.9 and 52.3 U/mg, respectively.

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