Untitled

Zakomirdina, Lyudmila N.; Kulikova, Vitalia V.; Gogoleva, Olga I.; Dementieva, I.; Faleev, N. G.; Demidkina, Tatyana V.

doi:10.1023/a:1020975610046

Cited by 20 publications

(12 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the affinity of VcTrpase to S-benzyl-L-cysteine was 30.145×10 −3 M which was ∼150 times higher than that to S-methyl-L-cysteine (0.210× 10 −3 M). A similar pattern has been reported for EcTrpase and PvTrpase [29,35,36]. In this work, we detected no catalytic activity of VcTrpase toward L-phenylalanine and L-serine.…”

Section: Kinetic Parameters and Substrate Specificitysupporting

confidence: 91%

“…3). These peaks were also found in the Trpase from E. coli and P. vulgaris [20,28,29]. In fact, the spectrum of all the VcTrpase mutants was similar to that of the wild-type enzyme (data not shown).…”

Section: Cholerae Tnaa Gene Sequence and Vctrpasementioning

confidence: 73%

“…Using Ltryptophan as a substrate, the K m and k cat values of VcTrpase were 0.612×10 −3 M and 5.252 s −1 , respectively (Table 2), which were comparable to those of the enzymes from E. coli and P. vulgaris [20,29]. However, the affinity of VcTrpase to S-benzyl-L-cysteine was 30.145×10 −3 M which was ∼150 times higher than that to S-methyl-L-cysteine (0.210× 10 −3 M).…”

Section: Kinetic Parameters and Substrate Specificitymentioning

confidence: 76%

“…This may be due to a preferential interaction between the enzyme active site and a polar aromatic substrate such as L-tryptophan and S-benzyl-L-cysteine. Previous studies have shown that the substrate affinity of Trpase from many bacteria to these compounds was at the micromolar level [20,25,29,[35][36][37][38], and indicated that the binding of the enzyme to polar aromatic substrates facilitated catalytic activity [38]. Finally, the k cat and k cat /K m values of VcTrpase to L-tryptophan substrate were much higher than those for S-benzyl-L-cysteine and S-methyl-Lcysteine which confirmed the efficiency of this enzyme ( Table 2).…”

Section: Kinetic Parameters and Substrate Specificitymentioning

confidence: 99%

See 3 more Smart Citations

Characterization of Tryptophanase from Vibrio cholerae

Nuidate

Tansila

Chomchuen

et al. 2014

Appl Biochem Biotechnol

View full text Add to dashboard Cite

Tryptophanase (Trpase) is a pyridoxal phosphate (PLP)-dependent enzyme responsible for the production of indole, an important intra- and interspecies signaling molecule in bacteria. In this study, the tnaA gene of Vibrio cholerae coding for VcTrpase was cloned into the pET-20b(+) vector and expressed in Escherichia coli BL21(DE3) tn5:tnaA. Using Ni(2+)-nitrilotriacetic acid (NTA) chromatography, VcTrpase was purified, and it possessed a molecular mass of ∼49 kDa with specific absorption peaks at 330 and 435 nm and a specific activity of 3 U/mg protein. The VcTrpase had an 80 % homology to the Trpase of Haemophilus influenzae and E. coli, but only around 50 % identity to the Trpase of Proteus vulgaris and Porphyromonas gingivalis. The optimum conditions for the enzyme were at pH 9.0 and 45 °C. Recombinant VcTrpase exhibited analogous kinetic reactivity to the EcTrpase with K m and k cat values of 0.612 × 10(-3) M and 5.252 s(-1), respectively. The enzyme catalyzed S-methyl-L-cysteine and S-benzyl-L-cysteine degradation, but not L-phenylalanine and L-serine. Using a site-directed mutagenesis technique, eight residues (Thr52, Tyr74, Arg103, Asp137, Arg230, Lys269, Lys270, and His463) were conserved for maintaining enzyme catalysis. All amino acid substitutions at these sites either eliminated or remarkably diminished Trpase activity. These sites are thus potential targets for the design of drugs to control the V. cholerae Trpase and to further investigate its functions.

show abstract

Section: Kinetic Parameters and Substrate Specificitysupporting

confidence: 91%

Section: Cholerae Tnaa Gene Sequence and Vctrpasementioning

confidence: 73%

Section: Kinetic Parameters and Substrate Specificitymentioning

confidence: 76%

Section: Kinetic Parameters and Substrate Specificitymentioning

confidence: 99%

See 2 more Smart Citations

Characterization of Tryptophanase from Vibrio cholerae

Nuidate

Tansila

Chomchuen

et al. 2014

Appl Biochem Biotechnol

View full text Add to dashboard Cite

show abstract

“…Tryptophanase can degrade L-serine into pyruvate through β-elimination [22]. indole to produce L-tryptophan by β-replacement with competitive suppression of pyruvate production [24].…”

Section: Enzymatic Assay Of Pyruvate Production From D-serinementioning

confidence: 99%

Reaction pathway of tryptophanase-catalyzed l-tryptophan synthesis from d-serine

Shimada¹,

Ozaki²,

Saito³

et al. 2011

Journal of Chromatography B

View full text Add to dashboard Cite

Tryptophanase, L-tryptophan indole-lyase with extremely absolute stereospecificity, can change the stereospecificity in concentrated diammonium hydrogenphosphate solution.While tryptophanase is inert to D-serine in the absence of diammonium hydrogenphosphate, it can undergo L-tryptophan synthesis from D-serine along with indole in the presence of it. It has been well known that tryptophanase synthesizes L-tryptophan from L-serine through a β-substitution mechanism of the ping-pong type.However, a metabolic pathway of L-tryptophan synthesis from D-serine has remained unclear. The present study aims to elucidate it. Diammonium hydrogenphosphate plays a role in the emergence of catalytic activity on D-serine. The salt gives tryptophanase a 2 small conformational change, which makes it possible to catalyze D-serine.Tryptophanase-bound D-serine produces L-tryptophan synthesis by β-replacement reaction via the enzyme-bound aminoacrylate intermediate. Our result will be valuable in studying the origin of homochirality.

show abstract

The influence of thermal reaction and microbial transformation on the odour of human urine

Troccaz

Niclass

Anziani

et al. 2013

Flavour & Fragrance J

View full text Add to dashboard Cite

The typical stale urine odour is the consequence of thermal or bacterial degradation. Gas chromatography–mass spectrometry, equipped with a multi‐sniffing port for olfactive evaluation (GC‐MS‐O), was performed to analyse an organic extract of boiled urine originating from seven male donors. This analysis stressed the importance of guaiacol, 2‐methoxy‐4‐ and ‐6‐methyl phenol, 4‐vinyl‐guaiacol, indole, skatole and vanillin in urine malodour. Analysis of the headspace of the highly volatile compounds showed the occurrence of trimethylamine, methyl mercaptan and dimethyl sulfide. However, odour artefacts such as pyrazines, acetyl thiazole and sugar degradation products were formed during the boiling process and represented important background noise. In parallel, fermented urine samples were judged by sniffing to be more characteristic of a urine smell, due to the presence of methional, phenol, p‐cresol and α‐androstenol. The two urine‐isolated Enterobacteriaceae, Escherichia fergusonii and Morganella morganii (urease positive), were particularly efficient at increasing urine pH and generating phenol, p‐cresol, indole, dimethyl sulfide and trimethylamine after 3 days of incubation of sterile male urine at 37 °C. Streptococcus agalactiae produced a high level of α‐androstenol, whereas Micrococcus luteus CIP 103664 and isolated anaerobic bacteria did not produce any malodours. Analytical comparisons between boiled and fermented aged urine revealed that incubation of sterile urine with a bacterial mixture of E. fergusonii, Enterococcus faecalis, Citrobacter koseri, S. agalactiae and M. morganii produced a representative aged urine odour. Copyright © 2013 John Wiley & Sons, Ltd.

show abstract

Untitled

Cited by 20 publications

References 22 publications

Characterization of Tryptophanase from Vibrio cholerae

Characterization of Tryptophanase from Vibrio cholerae

Reaction pathway of tryptophanase-catalyzed l-tryptophan synthesis from d-serine

The influence of thermal reaction and microbial transformation on the odour of human urine

Contact Info

Product

Resources

About