1968 Volume 14 Issue 2 Pages 147-161
Mycelial mats of Aspergillus niger 1617 grown on cellophane membrane placed on agar media were examined for activities of enzymes related to phosphorus metabolism during the course of cultural development.
Most enzymes tested, phosphomonoesterase, pyrophosphatase, ribonuclease, and deoxyribonuclease, showed two pH optima at acid and neutral to slightly alkaline regions except phosphodiesterase, which had an optimum at pH 5.8. In general, enzymes showing higher pH optima were active in younger mycelia and those of lower pH optima were active in aged ones.
Ribonucleases of T1-type (optimum pH 6.0) together with T2-type (optimum pH 4.5) were found in younger mycelia, while that of T2-type was most active in aged mycelia. The latter enzyme was considered to be responsible for the ribosome degradation.