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Maximum production of alkaline serine protease by Bacillus alcalophilus subsp. halodurans KP 1239 was achieved after 24 h cultivation, at an initial pH of 7.6, on a medium containing 1.0% sodium citrate, 0.3% yeast extract, and 0.3% KH2PO4. The enzyme was purified to crystalline form from culture broth. The enzyme was most active at 60 degrees C and at pH 11.5. The molecular weight, isoelectric point and sedimentation coefficient in water at 20 degrees C were estimated as 29,000, 8.8 and 3.3S, respectively. The N-terminal amino acid sequence was Ala-Gln-Ser-Val-Pro-Trp-Gly-Ile-Ser-Arg-Val-Gln-Ala-Pro-Ala-Ala- His-Asn-Arg-Gly-. The enzyme shared its antigenic determinants with B. alcalophilus ATCC 21522 serine protease, but not with the subtilisins Carlsberg and BPN'.

Convergent synthesis of dolastatin 15 (1), a cytostatic depsipeptide isolated from the Indian Ocean sea hare, has been described. For construction of the backbone, a single-step condensation of peptide fragment 2 and pyrrolidone fragment 3 was successfully performed using 2-chloro-1,3-dimethyl-2-imidazolinium hexafluorophosphate (CIP) developed by us as an efficient coupling reagent. Coupling of an N-methylamino acid on solid support was first achieved using CIP for the efficient synthesis of peptide fragment 2. The effectiveness of CIP for the coupling of N-methylamino acids in solution and on solid support were clarified by the syntheses of model di-and tripeptides.

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Convergent synthesis of (−)-mirabazole C (1), a tetra thiazoline/thiazole alkaloid isolated from blue-green alga, has been described. The successive thiazoline rings of (−)-mirabazole C were formed by a single-step cyclization mediated by TiCl4 treatment of tripeptide amide 4. Convergent synthesis of the key intermediate 33 derived from three 2-methylcysteine residues was first achieved using a newly developed coupling reagent, 2-chloro-1,3-dimethylimidazolidium hexafluorophosphate (CIP). The effectiveness of CIP for the coupling of α,α-dialkyl amino acids and the reaction pathway of the activation were clarified by the syntheses of model peptides containing an α,α-dimethylamino acid. A practical method of asymmetric synthesis of 2-methylcysteine by alkylation of 2,4-cis-oxazolidinone 23 has also been described.