Mechanism of Induced Circular Dichroism of Amino Acid Ester-Porphyrin Supramolecular Systems. Implications to the Origin of the Circular Dichroism of Hemoprotein

1994 ◽  
Vol 33 (16) ◽  
pp. 3558-3566 ◽  
Author(s):  
Tadashi Mizutani ◽  
Tadashi Ema ◽  
Takashi Yoshida ◽  
Thomas Renne ◽  
Hisanobu Ogoshi
Keyword(s):  
Circular Dichroism ◽  
Amino Acid ◽  
Acid Ester ◽  
Amino Acid Ester ◽  
Induced Circular Dichroism ◽  
Supramolecular Systems ◽  
Circular Dichroïsm

Eco-Friendly Synthesis of Peptides Using Fmoc-Amino Acid Chlorides as Coupling Agent Under Biphasic Condition

2020 ◽  
Vol 27 ◽  
Author(s):  
Santosh Y. Khatavi ◽  
K. Kantharaju
Keyword(s):  
Amino Acid ◽  
Acid Chloride ◽  
Acid Ester ◽  
Analytical Techniques ◽  
Peptide Bond ◽  
Amino Acid Ester ◽  
Acid Chlorides ◽  
Peptide Bond Formation ◽  
Green Protocol ◽  
Additional Base

Background: Agro-waste derived solvent media act as a greener process for the peptide bond formation using Nα - Fmoc-amino acid chloride and amino acid ester salt with in situ neutralization and coupling under biphasic condition. The Fmoc-amino acid chlorides are prepared by the reported procedure of freshly distilled SOCl2 with dry CH2Cl2. The protocol found many added advantages such as neutralization of amino acid ester salt and not required additional base for the neutralization, and directly coupling take place with Fmoc-amino acid chloride gave final product dipeptide ester in good to excellent yields. The protocol occurs with complete stereo chemical integrity of the configuration of substrates. Here, we revisited Schotten-Baumann condition, instead of using inorganic base. Objective: To develop green protocol for the synthesis of peptide bond using Fmoc-amino acid chloride with amino acid esters salt. Methods: The final product isolated is analyzed in several spectroscopic and analytical techniques such as FT-IR, 1H-, 13CNMR, Mass spectrometry and RP-HPLC to check stereo integrity and purity of the product. Conclusion: The present method developed greener using natural agro-waste (lemon fruit shell ash) derived solvent medium for the reaction and not required chemical entity.

A novel route for aspartame production by combining enzymatic and chemical reactions for industrial use

2020 ◽  
Vol 85 (2) ◽  
pp. 464-466
Author(s):  
Kenzo Yokozeki ◽  
Isao Abe
Keyword(s):  
Aqueous Solution ◽  
Amino Acid ◽  
Chemical Reactions ◽  
Acid Ester ◽  
Amino Acid Ester ◽  
Acyl Transferase ◽  
Enzymatic Production ◽  
Production Route ◽  
Industrial Use ◽  
Hcl Removal

ABSTRACT Here, we report a novel industrial aspartame production route, involving the enzymatic production of α-l-aspartyl-l-phenylalanine β-methylester from l-aspartic acid dimethylester and l-phenylalanine by α-amino acid ester acyl transferase. The route also involves the chemical transformation of α-l-aspartyl-l-phenylalanine β-methylester to α-l-aspartyl-l-phenylalanine methylester hydrochloride (aspartame hydrochloride) in an aqueous solution with methanol and HCl, followed by HCl removal to form aspartame.

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