The Ca2+-Induced Phase Transformation in Soybean Root Microsomal Membranes is a Consequence of Phospholipase Activation |
| |
Authors: | Caffrey Martin; Lew Roger R |
| |
Institution: | 1Section of Biochemistry, Molecular and Cell Biology, Clark Hall, Cornell University Ithaca, NY 14853 U.S.A.
2Section of Plant Biology, Division of Biological Sciences, Plant Science Building, Cornell University Ithaca, NY 14853, U.S.A. |
| |
Abstract: | Microsomes from soybean (Glycine max L.) roots contain a Ca2+-activatedphospholipase D which hydrolyzes phosphatidylethanolamine andphosphatidylcholine to phosphatidic acid. The phosphatidic acidbinds Ca2+ in the medium and undergoes a liquid crystal to gelphase transformation (measured by wide-angle x-ray diffraction).The gel phase formation in the microsomes half-saturates at1 to 10 mM Ca2+. The upper limit for the transition temperaturefor the microsomes is 10 to 10°C in the native state.After treatment with Ca2+, the transition temperature increasesto 35 to 50°C. Under the same experimental conditions, incubationwith 10 mM Ca2+ at 4°C causes an increase in phosphatidicacid content from 8 mole % to 49% with a concomitant decreasein phosphatidylethanolamine and phosphatidylcholine from about22% and 41%, respectively, to 14% each. These results suggest that Ca2+ effects in systems where Ca2+plays a multifunctional role be interpreted with caution.
3Present address: Department of Physiology, Yale UniversitySchool of Medicine, New Haven, CT 06510, U.S.A. (Received June 15, 1985; Accepted June 13, 1986) |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|