Stereochemical course of .gamma. replacement on an amino acid substrate in a pyridoxal phosphate dependent enzymic reaction

1980 ◽  
Vol 102 (24) ◽  
pp. 7368-7370 ◽  
Author(s):  
Michael N. T. Chang ◽  
Christopher Walsh
Keyword(s):  
Amino Acid ◽  
Pyridoxal Phosphate ◽  
Enzymic Reaction ◽  
Acid Substrate ◽  
Amino Acid Substrate

scholarly journals Use of β3-methionine as an amino acid substrate of Escherichia coli methionyl-tRNA synthetase

2020 ◽  
Vol 209 (2) ◽  
pp. 107435 ◽  
Author(s):  
Giuliano Nigro ◽  
Sophie Bourcier ◽  
Christine Lazennec-Schurdevin ◽  
Emmanuelle Schmitt ◽  
Philippe Marlière ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Trna Synthetase ◽  
Methionyl Trna Synthetase ◽  
Acid Substrate ◽  
Amino Acid Substrate

Human 20S proteasome activity towards fluorogenic peptides of various chain lengths

2016 ◽  
Vol 397 (9) ◽  
pp. 921-926 ◽  
Author(s):  
Wioletta Rut ◽  
Marcin Drag
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Kinetic Analysis ◽  
20S Proteasome ◽  
Fluorogenic Substrates ◽  
Catalytic Activities ◽  
Peptide Length ◽  
Chain Lengths ◽  
Acid Substrate ◽  
Amino Acid Substrate

Abstract The proteasome is a multicatalytic protease responsible for the degradation of misfolded proteins. We have synthesized fluorogenic substrates in which the peptide chain was systematically elongated from two to six amino acids and evaluated the effect of peptide length on all three catalytic activities of human 20S proteasome. In the cases of five- and six-membered peptides, we have also synthesized libraries of fluorogenic substrates. Kinetic analysis revealed that six-amino-acid substrates are significantly better for chymotrypsin-like and caspase-like activity than shorter peptidic substrates. In the case of trypsin-like activity, a five-amino-acid substrate was optimal.

The amino acid substrate of bovine tyrosine hydroxylase

1992 ◽  
Vol 21 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Marc M. Meyer ◽  
Paul F. Fitzpatrick
Keyword(s):  
Amino Acid ◽  
Tyrosine Hydroxylase ◽  
Acid Substrate ◽  
Amino Acid Substrate

scholarly journals The existence of an insulin-stimulated glucose and non-essential but not essential amino acid substrate interaction in diabetic pigs

2011 ◽  
Vol 12 (1) ◽  
pp. 25 ◽  
Author(s):  
Sietse J Koopmans ◽  
Jan VanderMeulen ◽  
Jan Wijdenes ◽  
Henk Corbijn ◽  
Ruud Dekker
Keyword(s):  
Amino Acid ◽  
Essential Amino Acid ◽  
Substrate Interaction ◽  
Acid Substrate ◽  
Amino Acid Substrate

Ketotic Hypoglycemia: An Amino Acid Substrate Limited Disorder*

1974 ◽  
Vol 38 (4) ◽  
pp. 521-530 ◽  
Author(s):  
MOREY W. HAYMOND ◽  
IRENE E. KARL ◽  
ANTHONY S. PAGLIARA
Keyword(s):  
Amino Acid ◽  
Ketotic Hypoglycemia ◽  
Acid Substrate ◽  
Amino Acid Substrate

scholarly journals Editing of non-cognate aminoacyl adenylates by peptide synthetases

1999 ◽  
Vol 342 (3) ◽  
pp. 715-719 ◽  
Author(s):  
Maja PAVELA-VRANCIC ◽  
Ralf DIECKMANN ◽  
Hans VON DÖHREN ◽  
Horst KLEINKAUF
Keyword(s):  
Amino Acid ◽  
Aromatic Amino Acids ◽  
Substrate Selection ◽  
Peptide Synthetases ◽  
Substrate Analogues ◽  
Wide Range ◽  
The Stability ◽  
Acid Substrate ◽  
Amino Acid Substrate ◽  
Selection Of

Non-ribosomally formed peptides display both highly conserved and variable amino acid positions, the variations leading to a wide range of peptide families. Activation of the amino acid substrate proceeds in analogy to the ribosomal biosynthetic mechanism generating aminoacyl adenylate and acyl intermediates. To approach the mechanism of fidelity of amino acid selection, the stability of the aminoacyl adenylates was studied by employing a continuous coupled spectrophotometric assay. The apo-form of tyrocidine synthetase 1 (apo-TY1) was used, generating an L-phenylalanyl-adenylate intermediate stabilized by the interaction of two structural subdomains of the adenylation domain. Adenylates of substrate analogues have shown variable and reduced degrees of stability, thus leading to an enhanced generation of pyrophosphate due to hydrolysis and continuous adenylate formation. Discrimination of the non-aromatic amino acids L-Leu and L-Met, or L-Phe analogues such as p-amino- and p-chloro-L-Phe derivatives, as well as the stereospecific selection of L-Phe, is supported by less-stable adenylate intermediates exhibiting elevated susceptibility to hydrolysis. Breakdown of the L-phenylalanyl intermediate utilizing 2′-deoxy-ATP as the nucleotide substrate was significantly enhanced compared with the natural analogue. Apo-TY1 engineered at positions involved in adenylate formation showed variable protection against hydrolysis. The results imply that stability of the aminoacyl intermediates may act as an essential factor in substrate selection and fidelity of non-ribosomal-peptide-forming systems.

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