Heat shock treatment releases Penicillium phosphoglycopeptide

Filtrates of heat (54 degrees) treated day-5 Penicillium fellutanum cultures contained 70 mg of peptidophosphogalactomannan-II; an unheated control contained 30 mg. The polymer contained up to 60 phosphodiesters, and 5-O-beta-D-galactofuranosyl, mannopyranosyl, amino acyl and 2-aminoethanol residues. Its 13C NMR spectrum was nearly identical with that of the control polymer. The major 31P NMR signal was phosphocholine phosphodiester at delta 0.22 ppm: significant phosphodiester signals occurred at delta 1.15, 1.33 and 1.47. Dilute mineral acid released galactofuranosyl residues from the mannan. Signals at delta 1.15-1.47 ppm were associated with molecules of mass less than 3500 and contained galactose, 2-aminoethanol and peptide(s). After this acid treatment, signals at delta 1.0-0.22 remained associated with the mannan. Heat released up to 4-fold more of peptidophosphogalactomannan-III compared with the untreated control; carbohydrate and phosphate content, per mg polymer, were reduced by 4- and 2-fold, respectively. A galactofuranosyl-, phosphoryl- and amino acyl-containing polymer of Mr greater than 14,000 was solubilized by alkali treatment of P. fellutanum cell walls.