Mycelianamide

Mycelium of Penicillium terlikowski was permeable to both L-[carboxyl-14C]phenylalanine and cyclo L-[carbonyl-14C]phenylalanyl-L-seryl. The former compound was incorporated well and the latter poorly into gliotoxin produced by stationary cultures of the organism. Mycelium of Penicillium patulum was permeablt to L-[CARBONYL-14C]tyrosyl and cyclo L-alanyl-d-[carbonyl-14C]tyrosyl. These cyclic depeptides were not incorporated into mycelianamide produced by stationary cultures of the organism, but both1carboxyl-14C]tyrosine were incorporated. The latter was incorporated in a specific manner into part of the mycelianamide molecule. The results did not support the postulate that the appropriate cyclic dipeptides, as outlined above, were free intermediates in the biosynthesis of gliotoxin or mycelianamide.

A screening aimed at obtaining a cholinesterase inhibitor of microbial origin was carried out using Pseudomonas butyrylcholinesterase. A mycelium-extract of a fungus strain, belonging to the genus Penicillium, was found to produce such an enzyme inhibitor. The inhibitor was purified and crystallized as colorless leaflets. From physical and chemical studies, the inhibitor was identified as being identical with an antibiotic, mycelianamide, though this compound was not known to have enzyme inhibitor activity. The kinetics of the inhibition of Pseudomonas butyrylcholinesterase were also studied. Horse serum cholinesterase and hog liver carboxylesterase were also inhibited by the isolated Penicillium C-81 inhibitor, but lipase and acetylcholinesterase were not.