Microbial Ribonucleases

Contenu

I. Introduction.- II. Classification of Enzymes Attacking RNA.- III. Distribution of RNases in Microorganisms.- Microorganisms of which RNA-Degrading Enzymes have been Investigated.- IV. Chemical Studies on Microbial RNases.- A. Introduction.- B. RNases of Aspergillus oryzae.- 1. RNase T1.- 2. RNase T2.- C. RNases of Streptomyces and Actinomyces.- 1. RNase of Streptomyces erythreus.- 2. RNase of Streptomyces albogriceolus.- 3. RNase of Actinomyces aureoverticillatus.- D. RNases of Ustilago.- 1. RNases of Ustilagosphaerogena and Ustilago zeae.- E. RNases of Neurospora crassa.- F. RNases of Azotobacter agilis (vinelandii).- G. RNase I of E. coli.- H. RNase of Aspergillus saitoi.- I. RNase of Bacillus subtilis.- 1. Extracellular RNases of Bacillus subtilis Strain H.- 2. Extracellular RNase of Bacillus subtilis Marburg Strain.- 3. Intracellular RNase of Bacillus subtilis.- J. Yeast RNase.- K. RNase II of E. coli.- L. RNase III of E. coli.- M. General Considerations.- 1. Ribonucleate Guaninenucleotido-2?-transferase (Cyclizing).- 2. Ribonucleate Purinenucleotido-2?-transferase (Cyclizing).- 3. Ribonucleate Ribonucleotido-2?-transferase (Cyclizing).- 4. Other RNases.- V. Physiological Role of RNA-Degrading Enzymes in Microorganisms.- A. Introduction.- B. Role of Intracellular Enzymes with Special Reference to E. coli.- 1. Mode of Existence.- a) Ribonuclease I (Ribosomal "Latent" Ribonuclease).- b) Ribonuclease II (Potassium Activated Ribonuclease).- c) Polynucleotide Phosphorylase.- 2. Physiological Role.- a) Roles in Metabolism of RNA.- b) Other Probable Roles.- 3. Control Mechanism of RNase Activity.- C. Role of Extracellular Enzymes.- VI. Concluding Remarks.- References.