Fungal membrane-bound

The fungal metabolite scyphostatin (Fig. 7) is a potent, reversible inhibitor of membrane-bound Mg +-dependent neutral sphingomyelinase (nSMase), thereby interfering with the generation of ceramide (102, 103). The activity of nSMases is sensitive to the cellular redox state, for example, the ratio of glutathione in the reduced versus the oxidized form (104, 105). The famesyltransferase inhibitor manumycin A, a polyenamide produced by the Streptomyces species, also inhibits nSMase irreversibly (106). 

Azoles inhibit 14-a-sterol demethylase, a microsomal CYP that is essential for ergosterol biosynthesis (Figure 48-1). This results in the accumulation of 14-a-methylsterols that disrupt the packing of acyl chains of phospholipids and impair the functions of membrane-bound enzymes such as ATPase and those of the electron transport system, resulting in inhibited fungal growth. 

Toward Understanding the Structure, Biosynthesis, and Function of a Membrane-Bound Fungal Glycopeptide Structural Studies... 

Cytoplasmic Peptidophosphogalactomannan. Fungal peptido-galactomannans have been extracted from powdered preparations (43). However, we were unable to obtain phosphogalactomannan from the cell walls of 3-day cultures of charlesii (20). When we examined extracts of P. charlesii cells we found galactofurano-syl residues both in a soluble cytoplasmic and a membrane-bound cytoplasmic fraction. 

Ebelaetones. Enzyme inhibitors with /3-lactone structure from cultures of Streptomyces aburaviensis. E. A C20H34O4, Mr 338.49, needles, mp. 86 °C, [a] - 221 ° (CHjOH)) and . B C2 H3 04,Mr352.51,needles,nip. 77 °C, Icc]d -203° (CH3OH) inhibit membrane-bound esterases, lipases, and aminopeptidases of animal cells as well as cutinases of fungal cells (antifungal activity). 

Polyene absorption by fungal membranes can be inhibited by agents with a high affinity for sterols, e.g. digitonin [161—164]. Digitonin also releases bound polyenes from membranes. 

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