Fungal Extracellular RNases (Review)

Studies of certain fungal extracellular RNases mainly isolated from representatives of the genera Aspergillus and Penicillium are reviewed. The isolation of these enzymes in highly purified states in the 1970s and 1980s strongly stimulated further studies of their structure, functions, and mechanisms of action. This also promoted the use of RNases as catalysts in oligoribonucleotide syntheses and as objects of comparative and evolutionary biochemical and other studies. Results of determinations of the primary, secondary, and spatial structures of guanyl-specific fungal RNases are reviewed. These studies revealed considerable homology within the subfamilies of fungal, bacterial, and actinomycete RNases. Characteristics of the nonspecific RNase Pb₂ are considered.