Ryoichi Tsurutani

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A new approach to enzymatic peptide synthesis by using aminoacyl-tRNA synthetase (ARS) as a catalyst has been investigated. Four ARSs (AspRS, HisRS, LeuRS and TyrRS) have been purified from a thermophilic bacterium, Bacillus stearothermophilus. By using TyrRS as a catalyst, tyrosine and leucinamide were shown to be condensed in the presence of ATP to give(More)
To have a comparatively more slowly releasing anticancer drug with effectiveness, Plachitin was prepared by chemical combination of CDDP and chitin (poly-N-acetyl-D-glucosamine). Chitin is absorbed by the living body over several months. To investigate the slow releasing property, it was implanted in thigh muscle of mice and rabbit. Pt level in different(More)
Plachitin, which is reconstituted by the combination of CDDP and chitin, has been reported to have a slow releasing property of CDDP and an antitumor effect. The antitumor effect and pharmacokinetics of Plachitin for intraarterial chemoembolization therapy were studied in rabbits using VX2 tumor inoculated in the hind limb. One gram of Plachitin contained(More)
The more potent inhibitory activity against angiotensin-converting enzyme (ACE) was excised from a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) preparation of Bacillus stearothermophilus by heating at 120 degrees C in 1 M AcOH-20 mM HCl, as compared with GAPDH preparations of yeast and pig. Sufficient excision of B. stearothermophilus ACE inhibitors(More)
We have already reported the slow releasing property and anticancer effect of Plachitin, which is reconstituted by combination of CDDP and chitin. This study deals in more detail with the slow releasing property, and the renal complications and the effectiveness for solid tumor were examined. After implantation of Plachitin subcutaneously in the abdominal(More)
A novel method of dipeptide synthesis is described that can be carried out in aqueous solution and does not require complicated protecting and deprotecting procedures. An analgesic neuropeptide named kyotorphin, H-Tyr-Arg-OH, was synthesized from unprotected tyrosine and arginine in a new enzymatic reaction catalyzed by immobilized tyrosyl-tRNA synthetase(More)
A new drug delivery system for local cancer chemotherapy was developed by chemical combination of chitin and cisplatin. When this material (Plachitin) was implanted in mice, high cisplatin concentrations were measured in the tissue around Plachitin for more than eight weeks without any nephrotoxicity. Local application of Plachitin improved the survival of(More)
Several kinds of dipeptide derivative were shown to be formed by the reactions of the aminoacyl adenylate-aminoacyl-tRNA synthetase complex and amino acid ester or amide. It was shown that the peptide bond could be formed by aminoacyl-tRNA synthetases even in the absence of the ribosome.
We designed an effective virus concentration method to prevent the infection with human immunodeficiency virus type 1 (HIV-1) in laboratories. The absorbent of Minicon concentrators (Amicon Division, M.R. Grace & Co.-Conn.) was changed to chitin, a mucopolysaccharide extracted from the shells of Japanese pink crab. HIV-1 in the supernatant of HIV-1 infected(More)
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