Characterization of ribonuclease activity of three S-allele-associated proteins of Petunia inflate

Anuradha Singh, Yunjun Ai, Teh Hui Kao

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


Three S-allele-associated proteins (S-proteins) of Petunia inflata, a species with gametophytic self-incompatibility, were previously found to share sequence similarity with two fungal ribonucleases, RNase T2 and RNase Rh. In this study, the S-proteins from P. inflata plants of S1S2 and S2S3 genotypes were purified to homogeneity by gel filtration and cation-exchange chromatography, and their enzymatic properties were characterized. The three S-proteins (S1, S2, and S3), with pairwise sequence identity ranging from 73.1 to 80.5%, were similar in most of the enzymatic properties characterized. The ribonuclease activity had a pH optimum of 7.0 and a temperature optimum of 50°C. Diethylpyrocarbonate at 1 millimolar almost completely abolished the ribonuclease activity; cupric sulfate and zinc sulfate at 1 millimolar reduced the ribonuclease activity of the three S-proteins by 50 to 75%. EDTA and RNasin had no inhibitory effect. All three S-proteins hydrolyzed polycytidylic acid preferentially, but varied in their nucleolytic activity toward polyadenylic acid and polyuridylic acid.

Original languageEnglish (US)
Pages (from-to)61-68
Number of pages8
JournalPlant physiology
Issue number1
StatePublished - 1991

All Science Journal Classification (ASJC) codes

  • Physiology
  • Genetics
  • Plant Science


Dive into the research topics of 'Characterization of ribonuclease activity of three S-allele-associated proteins of Petunia inflate'. Together they form a unique fingerprint.

Cite this