The Kinetic Demonstration of a Metastable Intermediate in a Nucleophilic Displacement at a Thiol-Ester Bond

1964 ◽  
Vol 86 (4) ◽  
pp. 738-739 ◽  
Author(s):  
Thomas C. Bruice ◽  
Leo R. Fedor
Keyword(s):  
Ester Bond ◽  
Thiol Ester ◽  
Nucleophilic Displacement

Nucleophilic Displacement Reactions at the Thiol-Ester Bond of δ-Thiolvalerolactone

1963 ◽  
Vol 85 (11) ◽  
pp. 1659-1669 ◽  
Author(s):  
Thomas C. Bruice ◽  
J. J. Bruno ◽  
Wei-Shin. Chou
Keyword(s):  
Ester Bond ◽  
Thiol Ester ◽  
Nucleophilic Displacement ◽  
Displacement Reactions

Nucleophilic Displacement Reactions at the Thiol Ester Bond. V. Reactions of 2,2,2-Trifluoroethyl Thiolacetate

1967 ◽  
Vol 89 (9) ◽  
pp. 2121-2127 ◽  
Author(s):  
Maurice J. Gregory ◽  
Thomas C. Bruice
Keyword(s):  
Ester Bond ◽  
Thiol Ester ◽  
Nucleophilic Displacement ◽  
Displacement Reactions

scholarly journals Reduction of the beta-Cys-gamma-Glu thiol ester bond of human C3 with sodium borohydride.

1983 ◽  
Vol 258 (22) ◽  
pp. 13580-13586 ◽  
Author(s):  
M L Thomas ◽  
F F Davidson ◽  
B F Tack
Keyword(s):  
Sodium Borohydride ◽  
Ester Bond ◽  
Thiol Ester

scholarly journals Streptomyces K15 active-site serine dd-transpeptidase: specificity profile for peptide, thiol ester and ester carbonyl donors and pathways of the transfer reactions

1995 ◽  
Vol 307 (2) ◽  
pp. 335-339 ◽  
Author(s):  
J Grandchamps ◽  
M Nguyen-Distèche ◽  
C Damblon ◽  
J M Frère ◽  
J M Ghuysen
Keyword(s):  
Active Site ◽  
Kinetic Data ◽  
Transfer Reactions ◽  
Ester Bond ◽  
Penicillin Binding Protein ◽  
Thiol Ester ◽  
Ester Carbonyl ◽  
Simple Alternative ◽  
Scissile Bond ◽  
Enzyme Intermediate

The Streptomyces K15 transferase is a penicillin-binding protein presumed to be involved in bacterial wall peptidoglycan crosslinking. It catalyses cleavage of the peptide, thiol ester or ester bond of carbonyl donors Z-R1-CONH-CHR2-COX-CHR3-COO- (where X is NH, S or O) and transfers the electrophilic group Z-R1-CONH-CHR2-CO to amino acceptors via an acyl-enzyme intermediate. Kinetic data suggest that the amino acceptor behaves as a simple alternative nucleophile at the level of the acyl-enzyme in the case of thiol ester and ester donors, and that it binds to the enzyme.carbonyl donor Michaelis complex and influences the rate of enzyme acylation by the carbonyl donor in the case of amide donors. Depending on the nature of the scissile bond, the enzyme has different requirements for substituents at positions R1, R2 and R3.

scholarly journals Limulus α2-macroglobulin. First evidence in an invertebrate for a protein containing an internal thiol ester bond

1987 ◽  
Vol 248 (3) ◽  
pp. 703-707 ◽  
Author(s):  
P B Armstrong ◽  
J P Quigley
Keyword(s):  
Proteinase Inhibitor ◽  
Thermal Denaturation ◽  
Horseshoe Crab ◽  
Proteinase Inhibitors ◽  
Binding Activity ◽  
Ester Bond ◽  
Thiol Groups ◽  
Thiol Ester ◽  
Complement Proteins ◽  
Α2 Macroglobulin

Intra-chain thiol ester bonds are present in a limited number of proteins. The thiol ester class of proteins includes vertebrate alpha 2-macroglobulin and the complement proteins C3 and C4. We report here the first instance of a thiol ester protein from an invertebrate, the alpha 2-macroglobulin proteinase-inhibitor homologue present in the plasma of the American horseshoe crab Limulus polyphemus. Our evidence is of three kinds: (1) the proteinase-binding activity of Limulus alpha 2-macroglobulin is inactivated by the low-molecular-mass primary amine methylamine; (2) the native protein is subject to autolytic fragmentation during mild thermal denaturation, yielding fragments of approx. 125 kDa and 55 kDa, whereas the methylamine-treated protein is stable under these conditions of thermal treatment; (3) new thiol groups are generated rapidly during reaction of the protein with trypsin. The demonstration of the thiol ester bond in a protein from an ancient invertebrate provides evolutionary evidence for the importance of this bond in the function of plasma forms of the alpha 2-macroglobulin-like proteinase inhibitors.

On the Structure-Function Relationships of the Unique Proteinase Inhibitor Human α2 Macroglobulin

1998 ◽  
Vol 4 (S2) ◽  
pp. 986-987
Author(s):  
James K. Stoops ◽  
Steven J. Kolodziej ◽  
Usman Qazi ◽  
Norman J. Nolasco ◽  
Peter G.W. Gettins ◽  
...  
Keyword(s):  
Structural Change ◽  
Complement Activation ◽  
Proteinase Inhibitor ◽  
Vital Role ◽  
Ester Bond ◽  
Cleavage Sites ◽  
Thiol Ester ◽  
Bait Region ◽  
Α2 Macroglobulin ◽  
Structural And Functional Properties

Human α2 macroglobulin (α2M) has structural and functional properties that contribute to its uniqueness as proteinase inhibitor. It is the largest known (Mr=720,000) and the only natural proteinase inhibitor which has a broad range of reactivity and for which the reaction is irreversible. It has a vital role in the clearance of proteinases from the circulation and in regulating their activity in fibrinolysis, coagulation and complement activation.An α2M molecule can entrap two proteinase molecules such as chymotrypsin and trypsin and can therefore be considered to contain two functional domains. Each subunit in the homotetramer has a bait region with cleavage sites for nearly all known endoproteinases and an internal thiol ester bond. A proteinase cleaves the two bait regions within both functional units leading to an activation and cleavage of the thiol ester bonds. Consequently, α2M undergoes a major structural change resulting in the irreversible entrapment of the proteinase.

Invertebrate ?2-Macroglobulin: Structure-Function and the Ancient Thiol Ester Bond

1994 ◽  
Vol 712 (1 Primordial Im) ◽  
pp. 131-145 ◽  
Author(s):  
JAMES P. QUIGLEY ◽  
PETER B. ARMSTRONG
Keyword(s):  
Structure Function ◽  
Ester Bond ◽  
Thiol Ester
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