| Co-Investigator(Kenkyū-buntansha) |
YUBISUI Toshitsugu Oita Medical University, Associate Professor, 医学部, 助教授 (00019564)
TAKESHITA Masazumi Oita Medical University, Professor, 医学部, 教授 (50019551)
YOSHIDA Satoshi Oita Medical University, Medicine, Associate Professor, 医学部, 助教授 (50158440)
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| Research Abstract |
(1) The condensation activity for long-chain tatty acid was largely decreased in microsomes of isolated oligodendroslia (OLG) cells, and this decrease was caused by the change of microsomal neiibrane structure. When OLG cells were subjected to cell culture for one day with cyclic AMP analogue, condensing enzymes were distributed in microsomal membranes during culture depending on the development of cytoskeletons and also depending on enzyme species.
(2)The purified microsomal membranes were aggregated around the microtubules when ATP and GTP were included in the reaction medium, which was observed by a microscope. When microtubules were interacted with microsomal membranes, the condensation activity for the endogenous tatty acid was decreased by 30-40%, whereas that for exogenous acyl-CoA was not.
(3)The condensation activities for polyunsaturated fatty acids in rat brain microsomes were maintained high in the post-myelination period. When multiple fatty acid substrates were incubated to
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gether, the condensation activity for each tatty acid was inhibited with each other in a non-competitive manner. This inhibition manner may contribute in some part for the tatty acid homeostasis in brain.
(4)The change of membrane fluidity, or membrane disorder, by 1-5 aN calcium ion in brain microsomes was detected by Fourier transform infrared spectroscopy. Under this condition, the condensation activity for several kinds of fatty acids was increased 2- to 3-fold. This activation was caused by a change of interaction between acyl-CoA synthetase and condensing enzyme, and by a change of transfer efficiency of acyl-CoA substrates from acyl-CoA synthetase to condensins enzyme.
(5)The calcium uptake and release in microsomal membranes were largely inhibited in the presence of 18 : 4(n-3)fatty acid and malony-CoA, but not in the presence of only 18 : 4 or malonyl-CoA alone or 18 : 3(n-6)plus malonyl-CoA. ATP alone decreased the scattering of light by microsomal membrane, and under this condition the volume of microsome was increased more than twice as detected by a microscope, but without any change of condensation activity. This suggests that the elonsation system for 18 : 4(n-3)affects on the calcium mobility in microsomes, but the physiological concentration of calcium ion increased the condensation activity for polyunsaturated fatty acids with only 30 %. Less
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