Sequential synthesis and secretion of pectinases by Penicillium frequentans

Penicillium frequentans synthesized eleven polygalacturonases and three pectinesterases when grown in the presence of pectin, sodium polypectate or monogalacturonic acid. When glucose was the sole carbohydrate source in the medium two of these polygalacturonases and one pectinesterase were produced. The enzymes produced under any of these conditions degraded pectic substrates to mono‐galacturonic acid, suggesting that this monosaccharide or its metabolites should induce the pectino‐lytic complex. All pectinesterases and most of the extracellular polygalacturonases were synthesized after the 2 nd hour of incubation. The pectinases produced by Penicillium frequentans were not secreted at the same time but after 5 hours of incubation all of them could be detected outside the cell those detected only inside the cell were probably membrane‐associated or unglycosylated forms of the extracellular pectinases.