Yoshio Inouye

In vitro antiviral activity of polyoxomolybdates. Mechanism of inhibitory effect of PM-104 (NH4)12H2(Eu4(MoO4(H2O)16(Mo7O24)4) · 13H2O on human immunodeficiency virus type 1

A screening for inhibitors of human immunodeficiency virus type 1 (HIV-1) among various types of isopolyoxomolybdates and heteropolyoxomolybdates was carried out by using an in vitro assay system measuring the cytopathogenicity of HIV-1 in CD4+ human MT-4 cells. A novel heteropolyoxomolybdate named PM-104 with the chemical formula (NH4)12H2(Eu4(MoO4)(H2O)16(Mo7O24)4).13H2O was found to be associated with potent anti-HIV-1 activity. PM-104 interferes with virus infection at a very early step such as adsorption and/or penetration into the cells. In addition to the cytopathic effect of HIV-1 on MT-4 cells, syncytium formation between mock-infected MOLT-4 cells and MOLT-4 cells chronically infected with either HIV-1 or HIV-2 is suppressed by PM-104. PM-104 also blocks the replication of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). The antiviral properties of PM-104 could be attributed to the combined effect of europium atoms and its peculiar three-dimensional anion structure.

Dimeric Macrocyclic Polyamines with Potent Inhibitory Activity against Human Immunodeficiency Virus

The structure-activity relationships of monomeric and dimeric macrocyclic polyamines were studied in an attempt to find potent inhibitors of human immunodeficiency virus (HIV) types 1 and 2. In general, dimeric polyamines are superior as HIV inhibitors to their monomeric counterparts, and the activity of a dimer is proportional to that of its constituent monomers. For the monomeric compounds, the amount of positive charge on the monomer rings under physiological conditions was more important for anti-HIV activity than the ring size. On the basis of these findings, the 14-membered tetraamine cyclam was selected as the component of dimeric compounds with potentially high activity. Of the series of newly synthesized bicyclams, in which the monomeric cyclams were linked at each C-6 position, a compound with an aIkyI chain bridge three carbons in length was found to exhibit the maximum anti-HIV activity. For one particular strain (HIV-2GH-1), syncytium formation was inhibited by the bicyclams at a similar concentration to that required to inhibit the viral cytopathic effect.

Synthesis of novel streptonigrin 2-amide derivatives with 3,3′-(phenylphosphoryl)bis(1,3-thiazolidine-2-thione)

Novel streptonigrin 2-amide derivatives have been efficiently synthesized without protection by using 3,3′-(phenylphosphoryl)bis(1,3-thiazolidine-2-thione)(PPBTT) as a chemoselective condensing agent.

Affinity chromatography of alkinonase A on N-carbobenzoxy-glycyl-leucyl-aminohexyl-Sepharose.

N-Carbobenzoxy-glycyl-leucyl-aminohexyl-Sepharose was found to be an effective affinity adsorbent for alkinonase A, an alkaline metalloendopeptidase of Streptomyces violaceorectus. The enzyme was adsorbed on this affinity adsorbent at pH 9.0 and eluted at pH 7.0. The purified enzyme was shown to be homogeneous by polyacrylamide gel electrophoresis, and the molecular weight of the enzyme was estimated to be 35000. The kinetics of the enzyme was studied using N-carbobenzoxy-glycyl-leucine amide as a substrate. The Km value decreased with increase of pH in the range of 6.0-9.0. The optimum pH for casein hydrolysis was 9.0-9.5, but the specificity rate constant (kcat / Km) in Tris-HCl (pH 7.0) was 9 times higher than that in Tris-HCl (pH 9.0) due to the much higher ratio of kcat values. No remarkable change in the relative rate constant was observed, when the leucine residue was replaced by phenylalanine in N-carbobenzoxy-glycyl-leucine amide. The replacement of the glycine moiety of the peptide with tryptophan or proline, however, markedly decreased the relative rate constant.