Translocation of presecretory proteins across the cytoplasmic membrane of Escherichia coli requires several Sec proteins and two kinds of energies, adenosine triphosphate (ATP) and a proton motive force. In vitro assay system established for the analysis of protein translocation revealed that ATP and the proton motive force play different roles in protein translocation. SecA, a peripheral membrane protein, was shown to be essential for in vitro protein translocation. SecE and SecY, both of which are integral membrane proteins, were purified from E. coli cells overproducing these proteins, and reconstituted into proteoliposomes. The reconstituted proteoliposomes exhibited protein translocation activity in the presence of ATP and SecA, indicating that SecE and SecY as well as SecA are indispensable components of protein translocation machinery. In this paper, the molecular mechanism of protein translocation across the membrane of E. coli is discussed based on the recent data obtained by both in vitro and reconstitution systems.

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The progress in the total synthesis of tetronic acid-containing macrolides (tetronolide, kijanolide, and chlorothricolide) and ionophore antibiotics (tetronomycin and tetronasin) is described.

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Enrichment of complex type N-linked sugar chains containing the Galβ1→4GlcNAcβ1→6 (Galβ1→4GlcNAcβ1→2) Man group was found to be the structural background of Warren-Glick phenomenon. This alteration is induced by enhanced expression of N-acetylglucosaminyltransferase V in malignant cells. The phenomenon is positively correlated with the tumorigenicity and the potency of blood-borne metastasis of tumor cells. Further investigation of the surface sugar chains of lectin mutants of mouse B16 melanoma revealed that the occurrence of sialylated tetraantennary sugar chains is essential for the metastasis of tumor cells.

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The ethanol precipitate fraction (RG-WP) obtained from the hot water extract from rhizome of Rehmannia glutinosa LIBOSCH. f. hueichingensis HSIAO is mainly composed of pectin-like polysaccharide, and exhibited hypoglycemic activity in normal and streptozotocin-induced mice by intraperitoneal administration of the fraction. The results obtained after chemical modification and proteinase treatments of RG-WP suggest that the activity exists in the polysaccharide moiety. Furthermore, the effect of RG-WP on the activities of enzymes responsible for the glucose metabolism in the liver of normal mouse was studied to elucidate the mechanism of the hypoglycemic activity. Administration of RG-WP to normal mice significantly increased the activities of hepatic glucokinase and glucose-6-phosphatase dehydrogenase, but decreased those of hepatic glucose-6-phosphatase and phosphofructokinase. RG-WP stimulated the secretion of insulin and reduced the glycogen content in the liver of normal mouse.

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Crystal morphology and crystal habit of phenytoin crystals were studied by the immersion method using a polarizing microscope. Several kinds of phenytoin materials, which had been confirmed to be lying on the same orientation by measuring key refractive indices, were photographed under crossed polars. The relationship between the patterns of retardation colors and the shapes of the phenytoin crystals were analyzed quantitatively using the chart indicating the relation of thickness to retardation colors, and concurrently several necessary facial angles were measured. On the basis of these results as well as edge angles measured under a microscope a stereographic projection was drawn finally, and an orthorhombic symmetry, an axial ratio and some facial angles were determined. Several kinds of crystal habits observed from the photographs were drawn by the classic crystallographic habit drawing method using the stereographic projection.

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The retention behavior and selectivity of 30 kinds of phenyl-modified porous glasses and silicas, prepared from solutions of phenyldimethylchlorosilane, diphenylmethylchlorosilane or triphenylchlorosilane in xylene, were studied by high-performance liquid chromatography using carbamazepine and diphenylhydantoin as model compounds. From the elemental data for carbon, the maximum number of bonded phenyl groups per gram (mean pore diameter, 15 nm, specific surface area, 217 m²/g, pore volume, 0.85 ml/g) on the diphenyl-bonded glass surface was calculated to be 0.159×10²¹. Using various acetonitrile-0.01 M potassium dihydrogen phosphate mixtures as eluents, carbamazepine and diphenylhydantoin were separated on all the gels studied, but the degrees of resolution of the two compounds were different. With an increase in specific surface area on the glasses or silicas, the k' values of the solute increased.

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A highly sensitive, accurate and reproducible gas chromatographic method for the determination of a main metabolite, 2-[4, 5-bis (4-methoxy-phenyl) thiazol-2-yl] pyrrol-ylacetic acid (desethyl KBT-3022) of a new antiplatelet agent, ethyl 2-[4, 5-bis (4-methoxyphenyl) thiazol-2-yl] pyrrol-1-ylacetate (KBT-3022), in the human or dog plasma has been developed. Desethyl KBT-3022 in the plasma was extracted with a mixture of n-hexane and dichloromethane (1 : 1), and was derivatized using pentafluorobenzyl bromide. The obtained pentafluo robenzyl derivative of desethyl KBT-3022 in the plasma was separated by high-performance liquid chromatography. After the separation, the pentafluorobenzyl derivative of desethyl KBT-3022 was detected by gas chromatography. Gas chromatography was performed with a Ultra 1 column (12 m×0.22 mm i. d., film thickness 0.33μm), using an electron capture detector. 2-[2-{4, 5-Bis (4-methoxyphenyl) thiazol-2-yl} pyrrol-1-yl] propionic acid was used as an internal standard. The detection limit of desethyl KBT-3022 in the plasma was 0.2 ng/ml. The coefficients of variation were below 5.3%. This method was applied to the determination of the plasma concentration of desethyl KBT-3022 after oral administration of KBT-3022 to dogs.

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