• The Korean Journal of Physiology
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• v.22 no.2
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• pp.163-177
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• 1988

The $Ca^{2+}-ATPase$ of sarcoplasmic reticulum (SR) was solubilized and reconstituted into a mixture of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) of varying ratios in order to assess the effect of physical states of phospholipids on the incorporation and functions $Ca^{2+}-ATPase$. On the basis of the spectral data of Ca-arsenazo III, the $Ca^{2+}$ uptake of SR was increased linearly as the PC content increased in the reconstituted vesicles. The ATP hydrolysis activity also increased as PC content increased up to 25% and then decreased slightly as the PC content further increased. On the other hand the incorporation of $Ca^{2+}-ATPase$ into the reconstituted vesicls occured maximally at 25% PC and 75% PE mixture which is known to have a non-bilayer structure in reconstitution system. From the above results it is clear that preexisting defects in the lipid bilayer promote protein incorporation into the bilayer during reconstitution and lamellar structure of the bilayer facilitates the $Ca^{2+}-ATPase$ function.

• Journal of the Korean Chemical Society
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• v.38 no.7
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• pp.502-508
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• 1994

The measurement of trace amounts of uranium(VI) and thorium(VI) in the solutions containing high concentration of dissolved salts was carried out. The procedure using reversed phase liquid chromatography with trace enrichment techniques has been developed to cope with the high salt content of the samples. 2 ml of sample were passed through a small C_{18}$ reversed phase enrichment column with ${\alpha}$-HIBA eluent (0.11 M, pH 5.5) where the uranium and thorium were separated from other constituents and concentrated. The uranium and thorium were then backflushed from the column onto a deactivated C_{18}$ reversed phase analytical column where furthe separation was achieved with a mixed eluent (pH3.0, 0.17M ${\alpha}$-HIBA/0.0038 M 1-pentanesulfonate). The separated species were determined spectrophotometrically by postcolumn reaction with Arsenazo III, the chromogenic reagent. Detection limits were found within 1 ppb range for both species.

• BMB Reports
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• v.30 no.3
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• pp.229-233
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• 1997

Indolicidin has been known to have a broad spectrum of antimicrobial activities against Gram negative and positive bacteria. Its eight analogues were chemically synthesized. The analogue design was based on the analysis of sequence to elucidate the role of some residues in the antibacterial mechanism of indolicidin. Bactericidal activities were assayed against Escherichia coli and Proteus vulgaris, and the membrane perturbing abilities of the peptides were assayed using a dye containing liposome. Among the eight analogues, $[Gly^4, Gly^6]-Indo,\;[Ile^6,Ile^8]-Indo,\;[Lys^{12}]-Indo$ and $[Thr^2,Tyr^9]-Indo$ showed enhanced antibacterial activities. These results suggest that proline and cationic residues are important in the bactericidal activity of indolicidin. We tried to describe the antimicrobial mechanism of indolicidin with these results.