Nmr study of poly(aspartic acid). II. α- and β-Peptide bonds in poly(aspartic acid) prepared by common methods

Biopolymers ◽  
1981 ◽  
Vol 20 (8) ◽  
pp. 1615-1623 ◽  
Author(s):  
V. Saudek ◽  
H. Pivcová ◽  
J. Drobník
Biopolymers ◽  
1981 ◽  
Vol 20 (8) ◽  
pp. 1605-1614 ◽  
Author(s):  
H. Pivcová ◽  
V. Saudek ◽  
J. Drobník ◽  
J. Vlasák

2017 ◽  
Vol 2017 ◽  
pp. 1-16
Author(s):  
Toratane Munegumi ◽  
Takafumi Yamada

The thermal reactions of amino acids have been investigated for pure organic synthesis, materials preparation in industry, and prebiotic chemistry. N-t-Butyloxycarbonyl aspartic acid (Boc-Asp) releases 2-butene and carbon dioxide upon heating without solvents. The resulting mixture of the free molten aspartic acid was dehydrated to give peptide bonds. This study describes the thermal reactions of N-t-butyloxycarbonyl peptides (Boc-Gly-L-Asp, Boc-L-Ala-L-Asp, Boc-L-Val-L-Asp, and Boc-Gly-Gly-L-Asp) having an aspartic residue at the carboxyl terminus. The peptides were deprotected upon heating at a constant temperature between 110 and 170°C for 1 to 24 h to afford polypeptides in which the average molecular weight reached 7800.


Author(s):  
Takuma Kato ◽  
Saki Kishimoto ◽  
Akiko Asano ◽  
Mitsunobu Doi

In the title homotripeptide {Boc-[Asp(OMe)]3-OPac}, C28H37N3O13, all peptide bonds adopt an s-trans conformation with respect to the N—H and C=O groups. In the crystal, N—H...O hydrogen bonds result in an infinite parallel β-sheet structure running along the b-axis direction. The Boc protecting group at the N-terminus of the peptide is disordered over two sites with occupancy factors of 0.504 (5) and 0.496 (5).


1988 ◽  
Vol 53 (5) ◽  
pp. 1086-1093 ◽  
Author(s):  
Václav Čeřovský ◽  
Jan Hlaváček ◽  
Jiřina Slaninová ◽  
Karel Jošt

Papain-catalyzed condensation of sodium salt of tert-butyloxycarbonyl-β-tert-butyloxyaspartyl-O4-sulfotyrosine (fragment 1-2) with methionyl-glycyl-tryptophyl-methionyl-aspartyl-phenylalanine amide (fragment 3-8) has been elaborated. Deprotection of the thus-obtained octapeptide afforded CCK-8 which exhibited full biological activities. Benzyloxycarbonylaspartyl-phenylalanine amide (fragment 7-8) was prepared using thermolysin without protecting the aspartic acid side chain. Attempted condensation of tert-butyloxycarbonylmethionyl-glycyl-tryptophan (fragment 3-5) with methionyl-aspartyl-phenylalanine amide (fragment 6-8), catalyzed by α-chymotrypsin, subtilisin or proteinase K, afforded the product (fragment 3-8) in only low yields. Further use of proteolytic enzymes for preparing other peptide fragments of the CCK-8 molecule without side chain protection is investigated.


1991 ◽  
Vol 109 (5) ◽  
pp. 690-698 ◽  
Author(s):  
Tadashi Ueda ◽  
Yoshimasa Isakari ◽  
Hidenori Aoki ◽  
Takanori Yasukochi ◽  
Shun-ichi Masutomo ◽  
...  

2017 ◽  
Author(s):  
Ingrid M. Weiss ◽  
Christina Muth ◽  
Robert Drumm ◽  
Helmut O.K. Kirchner

AbstractCalorimetry, thermogravimetry and mass spectrometry were used to follow the thermal decomposition of the eight amino acids G, C, D, N, E, Q, R and H between 185°C and 280°C. Endothermic heats of decomposition between 72 and 151 kJ/mol are needed to form 12 to 70 % volatile products. This process is neither melting nor sublimation. With exception of cysteine they emit mainly H2O, some NH3 and no CO2. Cysteine produces CO2 and little else. The reactions are described by polynomials, AA ^ a (NH3) + b (H2O) + c (CO2) + d (H2S) + e (residue), with integer or half integer coefficients. The solid monomolecular residues are rich in peptide bonds.


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