| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1992: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1991: ¥1,200,000 (Direct Cost: ¥1,200,000)
|
|---|
| Research Abstract |
1.Large scale cultivation of magnetotactic bacterium, Magnetospirillum magnetotacticum. We have tried to develop the method of large scale cultivation of magnetotactic bacterium, Magnetospirillum magnetotacticum by investigating the growth conditions such as oxygen concentration in the medium. Consequently, we could obtain 1.3g (wet wt.) cells from 10 L medium.
2.Purification and characterization of the components in the respiratory chain of magnetotactic bacterium, Magnetospirillum magnetotacticum. C-type and cdl-type cytochromes have been purified from the bacterium to an electrophoretically homogeneous state. Cytochrome c-550 showed almost the same spectral properties and molecular features as those of c type cytochromes of photosynthetic bacterium. Further, the ferrocytochrome c was rapidly oxidized with the membrane. These results suggest that cytochrome c-550 may function as the electron donor for the terminal oxidase in the respiratory chain. Cytochrome cd1 contained heme c and h
… More
eme d1 in the molecule. The cnzyme showed high nitrite -reduc-tase activity, although the physiological electron donor has not been elucidated in this study. On the other hand, we have purifed a novel hemoprotein from mangnetotactic bacterium, Magnetospirillum magnetotacticum. Although the hemoprotein which was tightly bound with the membrane showed very similar specral properties to those of "cytochrome a1". the protein contained no molecules of heme a. Two novel types of heme were detected in the hemoprotein by HPLC and FAB.Further, the hemoprotein hardly showed cytochrome c oxidase activity. Therefore, it seems unlikely thate the hemoprotein functions as the terminal oxidase in vivo.
3.Purification of Fe(III)-reductase from magnetotactic bacterium, Magnetospirillum magnetotacticum. We have tried to purify Fe(III)-reductase which was specifically found in the soluble fraction prepared from magnetotactic bacterium, Magnetospirillun magnetotacticum. The enzyme with the molecular weight of 51000 shows high NADH-Fe(III) oxidoreductase activity ; Km value and Vmax were 4muM and 170 nmol/min/mg protein, respectively. Now we have investigated the physiological function of Fe(III) reductase in the biosynthesis of magnetites. Less
|
