Detail of "1738-87-0"

Reference

Amino sugars

Amino sugars. CVI. The synthesis of N-(benzyloxycarbonyl)-3-O-[3,4,6-tri-O-acetyl-2-deoxy-2-(2,4-dinitroanili no)-.beta.-D-glucopyranosyl]-L-serine methyl ester, and its condensation with activated esters of amino acids. Garg, Hari G.; Jeanloz, Roger W. (Dep. Biol. Chem. Med., Harvard Med. Sch., Boston, Mass., USA). Carbohydr. Res., 52(1), 246-50 (English) 1976. CODEN: CRBRAT. DOCUMENT TYPE: Journal CA Section: 34 (Synthesis of Amino Acids, Peptides, and Proteins) Section cross-reference(s): 33 The title compd. I (R = CbZ = PhCH2O2C) (II) was prepd. by condensation of 3,4,6-tri-O-acetyl-2-deoxy-2-(2,4-dinitroanilino)-.alpha.-D-glucopyranos yl bromide with Cbz-Ser-OMe. Removal of the N-benzyloxycarbonyl group of II with HBr-AcOH followed by treatment with Et3N gave I (R = H) (III). Condensation of III Cbz-Ala-OC6H4NO2-p gave I (R = Cbz-Ala). Similarly prepd.Except for chemicals metioned above, 1738-87-0 and 1738-86-9 are also used. were I (R = Cbz-Gly), I (R = Cbz-Phe), and I (R = Cbz-Leu). .

Catalytic properties of porcine pancreatic elastase: a steady-state and pre-steady-state study

Catalytic properties of porcine pancreatic elastase: a steady-state and pre-steady-state study. Ascenzi, Paolo; Menegatti, Enea; Guarneri, Mario; Antonini, Eraldo (Fac. Med., Univ. Rome, Rome 00185, Italy). Mol. Cell. Biochem., 56(1), 33-8 (English) 1983. CODEN: MCBIB8.Chemicals with cas numbers 1738-87-0 and 3556-56-7 also play role. ISSN: 0300-8177. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) Pre-steady-state and steady-state kinetics for porcine pancreatic elastase-catalyzed hydrolysis of N-a-carbobenzoxy-L-alanine p-nitrophenyl ester, (ZAlaONp), one of the most favorable substrates for this serine protease, were studied at pH 4.0-8.0. The results are consistent with a min. 3-step mechanism: E + S J E-S J E-P + P1 J E + P2, where E, S, E-S, E-P, and P1 and P2 are the enzyme, the substrate, the enzyme-substrate complex, the acyl intermediate, and the products of hydrolysis, resp., and where the rate consts. for the forward reactions are designated k+1, k+2, and k+3 and those for the reverse reactions k-1, k-2, and k-3, resp. Under pre-steady-state conditions, where the initial enzyme concn. ([E0]) ? the initial substrate concn. ([S0]), the values of the dissocn. const. of the E-S complex (Ks = k-1/k+1) and of the individual rate consts. for the catalytic steps (k+2 and k+3) were detd. over the whole pH range explored. Under steady-state conditions, where [S0] ? [E0], the values of kcat and Km were obtained over the same pH range. The pH profiles of k+2, k+3, k+2/Ks, kcat, and kcat/Km reflect the ionization of a group, probably histidine-57, with a pKa value of 6.85. The values of Ks and Km are pH independent. The steady-state parameters for elastase-catalyzed hydrolysis of a no. of p-nitrophenyl esters of N-a-carbobenzoxy-L-amino acids were also detd. at pH 4.0-8.0 and compared with those of bovine b-trypsin and a-chymotrypsin. For all the substrates examd., the acylation step (k+2) is rate limiting in elastase catalysis at pH 4.0-8.0. The different catalytic behaviors of elastase, bovine b-trypsin, and bovine a-chymotrypsin are consistent with the known 3-dimensional structures of these serine proteases. .