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Production of diamino propionic acid ammonia lyase by a new strain of Salmonella typhimurium PU011.

Rupesh KR, PremKumar PL, Shiva Kumar VV, Jayachandran SS - BMC Microbiol. (2002)

Bottom Line: Following ammonium sulphate precipitation and passing through Sephadex G100, CM-Sephadex and DEAE-Sephacel for crude enzyme extract preparation, about 68-fold enzyme purity was obtained.The purified enzyme gave maximum activity at pH 8.0 and was stable up to 45 degrees C.The Km value for the substrate was found to be 0.685 mM, calculated from a Line Weaver Burk plot.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biotechnology, Pondicherry University, Kalapet, Pondicherry 605014, India. krrupesh@yahoo.com

ABSTRACT

Background: Seeds of the legume plant Lathyrus sativus, which is grown in arid and semi arid tropical regions, contain Diamino Propionic acid (DAP). DAP is a neurotoxin, which, when consumed, causes a disease called Lathyrism. Lathryrism may manifest as Neurolathyrism or Osteolathyrism, in which the nervous system, and bone formation respectively, are affected. DAP ammonia lyase is produced by a few microorganisms such as Salmonella typhi, Salmonella typhimurium and Pseudomonas, and is capable of detoxifying DAP.

Results: S. typhimurium PU011, a non-virulent bacterial strain isolated in our lab, was found to produce DAP ammonia lyase enzyme when grown in minimal medium containing DAP. There was a direct correlation between biomass yield and enzyme activity, until 16 h post inoculation in minimal medium containing DAP. Following ammonium sulphate precipitation and passing through Sephadex G100, CM-Sephadex and DEAE-Sephacel for crude enzyme extract preparation, about 68-fold enzyme purity was obtained. The purified enzyme gave maximum activity at pH 8.0 and was stable up to 45 degrees C. The Km value for the substrate was found to be 0.685 mM, calculated from a Line Weaver Burk plot.

Conclusion: A new bacterial strain, S.typhimurium PU 011, which is capable of producing DAP ammonia lyase, was isolated.

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Related in: MedlinePlus

Effect of pH on the Stability of DAP ammonia lyase. The crude enzyme extract was incubated in 10 mM phosphate buffer at different pH regimes and the enzyme activity measured. The enzyme activity is expressed as (U/mg) × 10-3.
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Figure 3: Effect of pH on the Stability of DAP ammonia lyase. The crude enzyme extract was incubated in 10 mM phosphate buffer at different pH regimes and the enzyme activity measured. The enzyme activity is expressed as (U/mg) × 10-3.

Mentions: With regard to specific activity of DAP ammonia lyase in different buffer systems at various pH regimes, it was found that the enzyme had a sharp pH optimum of 8.0 in phosphate buffer and at any pH less than 6 or more than 11 a drastic reduction in activity was observed (Fig 3). Vijiyalakhsmi et al. (1975) [6] also have observed an optimum pH of 8.0 for maximum DAP ammonia lyase enzyme activity produced by Pseudomonas. However, in their studies Tris HCl buffer at pH 8.0 was found to inhibit 50% of enzyme activity.


Production of diamino propionic acid ammonia lyase by a new strain of Salmonella typhimurium PU011.

Rupesh KR, PremKumar PL, Shiva Kumar VV, Jayachandran SS - BMC Microbiol. (2002)

Effect of pH on the Stability of DAP ammonia lyase. The crude enzyme extract was incubated in 10 mM phosphate buffer at different pH regimes and the enzyme activity measured. The enzyme activity is expressed as (U/mg) × 10-3.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC101404&req=5

Figure 3: Effect of pH on the Stability of DAP ammonia lyase. The crude enzyme extract was incubated in 10 mM phosphate buffer at different pH regimes and the enzyme activity measured. The enzyme activity is expressed as (U/mg) × 10-3.
Mentions: With regard to specific activity of DAP ammonia lyase in different buffer systems at various pH regimes, it was found that the enzyme had a sharp pH optimum of 8.0 in phosphate buffer and at any pH less than 6 or more than 11 a drastic reduction in activity was observed (Fig 3). Vijiyalakhsmi et al. (1975) [6] also have observed an optimum pH of 8.0 for maximum DAP ammonia lyase enzyme activity produced by Pseudomonas. However, in their studies Tris HCl buffer at pH 8.0 was found to inhibit 50% of enzyme activity.

Bottom Line: Following ammonium sulphate precipitation and passing through Sephadex G100, CM-Sephadex and DEAE-Sephacel for crude enzyme extract preparation, about 68-fold enzyme purity was obtained.The purified enzyme gave maximum activity at pH 8.0 and was stable up to 45 degrees C.The Km value for the substrate was found to be 0.685 mM, calculated from a Line Weaver Burk plot.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biotechnology, Pondicherry University, Kalapet, Pondicherry 605014, India. krrupesh@yahoo.com

ABSTRACT

Background: Seeds of the legume plant Lathyrus sativus, which is grown in arid and semi arid tropical regions, contain Diamino Propionic acid (DAP). DAP is a neurotoxin, which, when consumed, causes a disease called Lathyrism. Lathryrism may manifest as Neurolathyrism or Osteolathyrism, in which the nervous system, and bone formation respectively, are affected. DAP ammonia lyase is produced by a few microorganisms such as Salmonella typhi, Salmonella typhimurium and Pseudomonas, and is capable of detoxifying DAP.

Results: S. typhimurium PU011, a non-virulent bacterial strain isolated in our lab, was found to produce DAP ammonia lyase enzyme when grown in minimal medium containing DAP. There was a direct correlation between biomass yield and enzyme activity, until 16 h post inoculation in minimal medium containing DAP. Following ammonium sulphate precipitation and passing through Sephadex G100, CM-Sephadex and DEAE-Sephacel for crude enzyme extract preparation, about 68-fold enzyme purity was obtained. The purified enzyme gave maximum activity at pH 8.0 and was stable up to 45 degrees C. The Km value for the substrate was found to be 0.685 mM, calculated from a Line Weaver Burk plot.

Conclusion: A new bacterial strain, S.typhimurium PU 011, which is capable of producing DAP ammonia lyase, was isolated.

Show MeSH
Related in: MedlinePlus