Combinatorial synthesis of MUC1 glycopeptides: polymer blotting facilitates chemical and enzymatic synthesis of highly complicated mucin glycopeptides

The chemoselective polymer blotting method allows for rapid and efficient synthesis of glycopeptides based on a "catch and release" strategy between solid-phase and water-soluble polymer supports. We have developed a heterobifunctional linker sensitive to glutamic acid specific protease (BLase). The general procedure consists of five steps, namely (i) the solid-phase synthesis of glycopeptide containing BLase sensitive linker, (ii) subsequent deprotections and the release of the glycopeptide from the resin, (iii) chemoselective blotting of the glycopeptide intermediates in the presence of water-soluble polymers with oxylamino functional groups, (iv) sugar elongations using glycosyltransferases, and (v) the release of target glycopeptides from the polymer platform by selective BLase promoted hydrolysis. The combined use of the solid-phase chemical syntheses of peptides and the enzymatic syntheses of carbohydrates on water-soluble polymers would greatly contribute to the production of complicated glycopeptide libraries, thereby enhancing applicative research. We report here a high-throughput synthetic system for the various types of MUC1 glycopeptides exhibiting a variety of sugar moieties. It is our belief that this concept will become part of the entrenched repertoire for the synthesis of biologically important glycopeptides on the basis of glycosyltransferase reactions in automated and combinatorial syntheses.     

Preparation and pharmacological evaluation of 4-(1,4-benzoquinon-2-yl)-4-phenylbutanamides as potential cerebral protective agents.

A new series of 4-(1,4-benzoquinon-2-yl)-4-phenylbutanamides (2) were synthesized for evaluation of their pharmacological activities. All these compounds synthesized showed significant antilipidperoxidation (ALP) activities with brain homogenate in rats and some of them possessed a protective effect against hypobaric hypoxia in mice. Especially, a thiomorpholine derivative (2l, SUN-4757) showed a wide efficacy spectrum to a variety of experimental screening assays designed for cerebral protective agents, and it had a high LD50 value.     

A general method for construction of (<Emphasis Type="Italic">t</Emphasis>, <Emphasis Type="Italic">n</Emphasis>)-threshold visual secret sharing schemes for color images

This paper is concerned with the construction of basis matrices of visual secret sharing schemes for color images under the (t, n)-threshold access structure, where n ≥ t ≥ 2 are arbitrary integers. We treat colors as elements of a bounded semilattice and regard stacking two colors as the join of the two corresponding elements. We generate n shares from a secret image with K colors by using K matrices called basis matrices. The basis matrices considered in this paper belong to a class of matrices each element of which is represented by a homogeneous polynomial of degree n. We first clarify a condition such that the K matrices corresponding to K homogeneous polynomials become basis matrices. Next, we give an algebraic scheme for the construction of basis matrices. It is shown that under the (t, n)-threshold access structure we can obtain K basis matrices from appropriately chosen K − 1 homogeneous polynomials of degree n by using simple algebraic operations. In particular, we give basis matrices that are unknown so far for the cases of t = 2, 3 and n − 1.     

A first high enantiocontrol of an asymmetric tertiary carbon center attached with a fluoroalkyl group via Rh(I)-catalyzed conjugate addition reaction

Treatment of fluoroalkylated electron-deficient olefins with various boronic acids in the presence of a catalytic amount of Rh(I) coordinated with (S)-BINAP in toluene/H₂O at the reflux temperature for 3 h gave the corresponding conjugate addition products with high enantioselectivity in high yields.     

Rank 2 Ample Vector Bundles on Some Smooth Rational Surfaces

Several classification results for ample vector bundles of rank 2 on Hirzebruch surfaces, and on Del Pezzo surfaces, are obtained. In particular, we classify rank 2 ample vector bundles with _c2 less than seven on Hirzebruch surfaces, and with _c2 less than four on Del Pezzo surfaces.