[ Fungal extracellular ribonucleases (Review)]

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