Detail of "7606-79-3"

Reference

New contributions to the chemistry of the reactive dyeing of protein fibers

New contributions to the chemistry of the reactive dyeing of protein fibers. Altenhofen, U.; Baumann, H.; Zahn, H. (Dtsch. Wollforschungsinst., Rheinisch-Westfael. Tech. Hochsch. Aachen e.V., Aachen, Ger.). Proc. - Int. Wolltextil-Forschungskonf., 5th, Meeting Date 1975, Volume 3, 529-41. Edited by: Ziegler, Klaus. Dtsch. Wollforschungsinstitut Tech. Hochsch.: Aachen, Ger. (German) 1976. CODEN: 35LRAE. DOCUMENT TYPE: Conference CA Section: 39 (Textiles) The reaction of the pyrimidine dye (I) [63517-75-9] and the vinyl sulfone dye Remazol Brilliant Blue R (II) [2580-78-1] with peptide model compds., i.e., N.alpha.-acetylcysteine methylamide [10061-65-1], N.alpha.-acetylhistidine methylamide [6367-11-9], N.alpha.-acetyltyrosine methylamide [6367-14-2], N.alpha.-acetyllysine methylamide [6367-10-8], and N.alpha.-acetylglycine methylamide [7606-79-3] was monitored by means of thin-layer chromatog. and a Fortran computer program was used to det. the reaction velocity and rate of hydrolysis. While I reacted with the lysine, glycine, and histidine model compds. 10-25 times faster than I, the reaction velocity of I with the thiol group of the cysteine model compd. was .apprx.120 times that of I, indicating that level dyeings will be easier to obtain with I than with II. Under weakly acidic conditions at 80-95.degree. I reacts with the amino and imino groups of lysine and histidine and with the thiol group of cysteine, while the reaction with the phenolic hydroxyl group of tyrosine could be disregarded. The reaction of reactive dyes with wool in a wealky acidic liquor is attributed to an increase in the dissocn. of reactive groups at high temps., esp. the large increase in the dissocn. of lysine in comparison to tyrosine.

A point-charge force field for molecular mechanics simulations of proteins based on condensed-phase quantum mechanical calculations

A point-charge force field for molecular mechanics simulations of proteins based on condensed-phase quantum mechanical calculations. Duan, Yong; Wu, Chun; Chowdhury, Shibasish; Lee, Mathew C.; Xiong, Guoming; Zhang, Wei; Yang, Rong; Cieplak, Piotr; Luo, Ray; Lee, Taisung; Caldwell, James; Wang, Junmei; Kollman, Peter (Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA). Journal of Computational Chemistry, 24(16), 1999-2012 (English) 2003 John Wiley & Sons, Inc. CODEN: JCCHDD. ISSN: 0192-8651. DOCUMENT TYPE: Journal CA Section: 9 (Biochemical Methods) Section cross-reference(s): 6, 65 Mol. mechanics models have been applied extensively to study the dynamics of proteins and nucleic acids. Here we report the development of a third-generation point-charge all-atom force field for proteins. Following the earlier approach of Cornell et al., the charge set was obtained by fitting to the electrostatic potentials of dipeptides calcd. using B3LYP/cc-pVTZ/HF/6-31G** quantum mech. methods.Several reagents with their cas registry numbers 19701-83-8 and 7606-79-3 are used here. The main-chain torsion parameters were obtained by fitting to the energy profiles of Ace-Ala-Nme and Ace-Gly-Nme di-peptides calcd. using MP2/cc-pVTZ//HF/6-31G** quantum mech. methods. All other parameters were taken from the existing AMBER data base. The major departure from previous force fields is that all quantum mech. calcns. were done in the condensed phase with continuum solvent models and an effective dielec. const. of e = 4. We anticipate that this force field parameter set will address certain crit. short comings of previous force fields in condensed-phase simulations of proteins. Initial tests on peptides demonstrated a high-degree of similarity between the calcd. and the statistically measured Ramanchandran maps for both Ace-Gly-Nme and Ace-Ala-Nme di-peptides. Some highlights of our results include (1) well-preserved balance between the extended and helical region distributions, and (2) favorable type-II poly-proline helical region in agreement with recent expts. Backward compatibility between the new and Cornell et al. charge sets, as judged by overall agreement between dipole moments, allows a smooth transition to the new force field in the area of ligand-binding calcns. Test simulations on a large set of proteins are also discussed. .