Calcium ions and polyamines activate the plasma membrane-located 1,3-β-glucan synthase

✍ Scribed by J. Fink; W. Jeblick; W. Blaschek; H. Kauss

• Book ID: 104754693
• Publisher: Springer-Verlag
• Year: 1987
• Tongue: English
• Weight: 608 KB
• Volume: 171
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00395076

✦ Synopsis

Sucrose-density-gradient centrifugation and partitioning in a polyethylene glycol/dextran two-phase system were used to isolate plasmamembrane vesicles from microsomal preparations of soybean cell suspension cultures. Both methods resulted in the enrichment of the activity of a 1,3-/?glucan synthase which forms a polymer consisting of more than 99% of 1,3-1inked glucose (callose). Digitonin increases the 1,3-/?-glucan synthase activity in the various membrane fractions to a different degree, supporting the suggestion that this enzyme is vectorially arranged in the plasma membrane. The enzyme is greatly activated either by poly-L-ornithine or synergistically by Ca 2+ and spermine, indicating that the same enzyme is affected and exhibits the regulatory properties necessary for callose synthesis.