Configurational Stability of Sulfonyl Carbanions Generated by Decarboxylation Reaction

1962 ◽  
Vol 84 (8) ◽  
pp. 1496-1497 ◽  
Author(s):  
Donald J. Cram ◽  
Alan S. Wingrove
Keyword(s):  
Configurational Stability ◽  
Decarboxylation Reaction ◽  
Sulfonyl Carbanions

Stereoid cd-ring synthons from podocarpic acid by use of the barton radical decarboxylation reaction

1989 ◽  
Vol 30 (50) ◽  
pp. 7111-7114 ◽  
Author(s):  
E.Jane Cochrane ◽  
S.Warren Lazer ◽  
John T. Pinhey ◽  
John D. Whitby
Keyword(s):  
Decarboxylation Reaction

scholarly journals The Mechanism of the Tyrosine Transporter TyrP Supports a Proton Motive Tyrosine Decarboxylation Pathway in Lactobacillus brevis

2006 ◽  
Vol 188 (6) ◽  
pp. 2198-2206 ◽  
Author(s):  
Wout A. M. Wolken ◽  
Patrick M. Lucas ◽  
Aline Lonvaud-Funel ◽  
Juke S. Lolkema
Keyword(s):  
Phenyl Ring ◽  
Lactobacillus Brevis ◽  
Proton Motive Force ◽  
Proton Pumping ◽  
Hydroxyl Group ◽  
Transporter Gene ◽  
Tyrosine Decarboxylase ◽  
Rate Analysis ◽  
Substrate Analogues ◽  
Decarboxylation Reaction

ABSTRACT The tyrosine decarboxylase operon of Lactobacillus brevis IOEB9809 contains, adjacent to the tyrosine decarboxylase gene, a gene for TyrP, a putative tyrosine transporter. The two genes potentially form a proton motive tyrosine decarboxylation pathway. The putative tyrosine transporter gene of L. brevis was expressed in Lactococcus lactis and functionally characterized using right-side-out membranes. The transporter very efficiently catalyzes homologous tyrosine-tyrosine exchange and heterologous exchange between tyrosine and its decarboxylation product tyramine. Tyrosine-tyramine exchange was shown to be electrogenic. In addition to the exchange mode, the transporter catalyzes tyrosine uniport but at a much lower rate. Analysis of the substrate specificity of the transporter by use of a set of 19 different tyrosine substrate analogues showed that the main interactions between the protein and the substrates involve the amino group and the phenyl ring with the para hydroxyl group. The carboxylate group that is removed in the decarboxylation reaction does not seem to contribute to the affinity of the protein for the substrates significantly. The properties of the TyrP protein are those typical for precursor-product exchangers that operate in proton motive decarboxylation pathways. It is proposed that tyrosine decarboxylation in L. brevis results in proton motive force generation by an indirect proton pumping mechanism.

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