scholarly journals Calf chymosin as a catalyst of peptide synthesis

1992 ◽  
Vol 288 (3) ◽  
pp. 941-943 ◽  
Author(s):  
C A Abdel Malak
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Methyl Esters ◽  
Amino Acid Residues ◽  
Hydrophobic Amino Acid ◽  
Peptide Bonds ◽  
Aspartate Proteinase ◽  
Specificity Pattern ◽  
Adjacent Amino Acid

Calf chymosin was shown to catalyse peptide synthesis optimally over the range pH 4-5, giving satisfactory yields of methyl esters or p-nitroanilides of benzyloxycarbonyl tetra- to hexa-peptides, provided that hydrophobic amino-acid residues form the new peptide bonds. The effectiveness of the enzyme depends also on the nature of adjacent amino-acid residues. As an aspartate-proteinase with a characteristic specificity pattern chymosin would be useful for the synthesis of middle-length peptides.

scholarly journals Mitigating the Adverse Effects of Polychlorinated Biphenyl Derivatives on Estrogenic Activity via Molecular Modification Techniques

2021 ◽  
Vol 18 (9) ◽  
pp. 4999
Author(s):  
Wei He ◽  
Wenhui Zhang ◽  
Zhenhua Chu ◽  
Yu Li
Keyword(s):  
Amino Acid ◽  
Binding Site ◽  
Hydrophobic Interaction ◽  
Oestrogen Receptor ◽  
Polychlorinated Biphenyl ◽  
Hydrophobic Interactions ◽  
Estrogenic Activity ◽  
Average Distance ◽  
Amino Acid Residues ◽  
Hydrophobic Amino Acid

The aim of this paper is to explore the mechanism of the change in oestrogenic activity of PCBs molecules before and after modification by designing new PCBs derivatives in combination with molecular docking techniques through the constructed model of oestrogenic activity of PCBs molecules. We found that the weakened hydrophobic interaction between the hydrophobic amino acid residues and hydrophobic substituents at the binding site of PCB derivatives and human oestrogen receptor alpha (hERα) was the main reason for the weakened binding force and reduced anti-oestrogenic activity. It was consistent with the information that the hydrophobic field displayed by the 3D contour maps in the constructed oestrogen activity CoMSIA model was one of the main influencing force fields. The hydrophobic interaction between PCB derivatives and oestrogen-active receptors was negatively correlated with the average distance between hydrophobic substituents and hydrophobic amino acid residues at the hERα-binding site, and positively correlated with the number of hydrophobic amino acid residues. In other words, the smaller the average distance between the hydrophobic amino acid residues at the binding sites between the two and the more the number of them, and the stronger the oestrogen activity expression degree of PCBS derivative molecules. Therefore, hydrophobic interactions between PCB derivatives and the oestrogen receptor can be reduced by altering the microenvironmental conditions in humans. This reduces the ability of PCB derivatives to bind to the oestrogen receptor and can effectively modulate the risk of residual PCB derivatives to produce oestrogenic activity in humans.

The anti-leishmanial activity of dipeptide esters on Leishmania amazonensis amastigotes

Parasitology ◽  
1990 ◽  
Vol 100 (2) ◽  
pp. 201-207 ◽  
Author(s):  
C. Ramazeilles ◽  
L. Juliano ◽  
J. R. Chagas ◽  
M. Rabinovitch
Keyword(s):  
Amino Acid ◽  
Methyl Esters ◽  
Leishmania Amazonensis ◽  
Amino Acid Esters ◽  
Cysteine Proteinases ◽  
Hydrophobic Amino Acid ◽  
Structure Activity ◽  
Reduction Assay ◽  
Mtt Reduction ◽  
Acid Esters

SUMMARYL-Amino acid esters, such as L-Leu-OMe, kill Leishmania amazonensis amastigotes by a mechanism which appears to involve ester hydrolysis by cysteine proteinases located in the parasite megasomes. We have examined the killing of isolated amastigotes by L-dipeptide esters and derived some structure-activity correlations. Toxicity of the compounds for the parasites was measured by a tetrazolium (MTT) reduction assay. The results show that active dipeptide esters contained at least I hydrophobic amino acid (Leu, Ile, Val, Phe or Trp). The activity of homodipeptide methyl esters depended on the nature of the amino acid, as indicated by the following series: Phe-Phe-OMe < Val-Val-OMe < Leu-Leu-OMe < Trp-Trp-OMe < Ile-Ile-OMe. The nature of the amino acids in Leu-X-OMe and X-Leu-OMe was relatively unimportant when X was Phe, Trp or Val. However, when X was Ala or Gly, Leu-X-OMe was several-fold more active than X-Leu-OMe.

Enhanced stability of Cu2+–ATCUN complexes under physiologically relevant conditions by insertion of structurally bulky and hydrophobic amino acid residues into the ATCUN motif

2016 ◽  
Vol 45 (23) ◽  
pp. 9436-9445 ◽  
Author(s):  
Takaaki Miyamoto ◽  
Yuta Fukino ◽  
Shinichiro Kamino ◽  
Masashi Ueda ◽  
Shuichi Enomoto
Keyword(s):  
Amino Acid ◽  
Amino Acid Residues ◽  
Hydrophobic Amino Acid ◽  
Hydrophobic Residues ◽  
The Stability ◽  
Enhanced Stability

The stability of Cu2+–ATCUN complexes under physiologically relevant conditions is enhanced by inserting bulky and hydrophobic residues at positions 1 and 2 of the ATCUN peptide.

ChemInform Abstract: Cobalt(III)-Mediated Peptide Synthesis. Part 1. Cobalt(III)-Activated Amino Acid Methyl Esters and the Synthesis of Dipeptides.

1982 ◽  
Vol 13 (9) ◽  
Author(s):  
C. R. CLARK ◽  
R. F. TASKER ◽  
D. A. BUCKINGHAM ◽  
D. R. KNIGHTON ◽  
D. R. K. HARDING ◽  
...  
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Methyl Esters ◽  
Acid Methyl ◽  
Amino Acid Methyl Esters
Sign in / Sign up

Export Citation Format

Share Document