Resins sold by several companies were examined for swelling, uniformity of beads, and substitution in the case of resins sold with the first amino acid attached. Effects of resin swelling, uniformity, and substitution on the solid phase synthesis of long, structured and/or branched peptides were evaluated.
The synthetic peptide Chymohelizyme-1 (CHZ-1) exhibits esterase activity against carbobenzoxytyrosine p-nitrophenyl ester (ZTONP), carbobenzoxyalanine p-nitrophenyl ester (ZAONP), and t-butyloxy-carbonyltyrosine p-nitrophenyl ester (BocTONP). However, earlier reports of catalytic activity against less labile esters and amides have proven to be incorrect. The major reason for the errors appears to have been the omission of certain controls in the previous work. Although the catalytic triad does not appear to be functioning as designed, the catalytic activity of CHZ-1 does depend on the integrity of its primary structure. The pH dependence of hydrolysis of ZTONP points to general-base catalysis, whereas a preference for hydrophobic substrates suggest that the structure of CHZ-1 is performing some other role in assisting catalysis.
3‐Nitro‐2‐pyridinesulfenyl chloride (NpysCl) is the starting material for the synthesis of N‐, O‐ and S‐Npys‐protected amino acids. Two efficient, novel synthetic routes to NpysCl are described. The stability of NpysCl was determined in a variety of solvents, with and without base, to determine the most suitable solvent and base for the synthesis of N‐Npys amino acids. The syntheses of Npys‐Ala and Boc‐Lys(Npys) tert‐butylammonium salt are also described.
The optimization of a technology for the Ti02-mediated solar photocatalysis of atrazine is described. The target users of this technology might be agrochemical dealers, manufacturers, and possibly farmers. Studies were performed to determine the ideal cover material for such a reactor based on UV light transmitting properties. The best cover material was a W transmitting acrylic. The Ti02 employed for this technology was bound to fiberglass mesh. The effects of mesh amount, stirring, water impurities, concentration of pesticide, and source of W light (mercury vapor lamp vs. solar) were also determined. The most efficient photocatlysis was achieved using five layers of mesh, a stirred reaction, water low in carbonate and other ions, a dilute waste stream, and solar irradiation rather than a mercury-vapor lamp. The formation and disappearance of eight intermediates were followed in a 2429 h indoor experiment comparing pure and formulated atrazine. A modified reaction mechanism was proposed based on studies of the detected intermediates.
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