Identification and enzymatic characterization of acid phosphatase from Burkholderia gladioli.
BACKGROUND
The genus Burkholderia is widespread in diverse ecological niches, the majority of known species are soil bacteria that exhibit different types of non-pathogenic interactions with plants. Burkholderia species are versatile organisms that solubilize insoluble minerals through the production of organic acids, which increase the availability of nutrients for the plant. Therefore these bacteria are promising candidates for biotechnological applications.


RESULTS
Burkholderia sp. (R 3.25 isolate) was isolated from agricultural soil in Ponta Grossa-PR-Brazil and identified through analysis of the 16S rDNA as a strain classified as Burkholderia gladioli. The expression of membrane-bound acid phosphatase (MBAcP) was strictly regulated with optimal expression at a concentration of phosphorus 5 mM. The apparent optimum pH for the hydrolysis of p-nitrophenylphosphate (PNPP) was 6.0. The hydrolysis of PNPP by the enzyme exhibited a hyperbolic relationship with increasing concentration of substrate and no inhibition by excess of substrate was observed. Kinetic data revealed that the hydrolysis of PNPP exhibited cooperative kinetics with n = 1.3, Vm = 113.5 U/mg and K0.5 = 65 μM. The PNPPase activity was inhibited by vanadate, p-hydroxymercuribenzoate, arsenate and phosphate, however the activity was not inhibited by calcium, levamisole, sodium tartrate, EDTA, zinc, magnesium, cobalt, ouabain, oligomycin or pantoprazol.


CONCLUSIONS
The synthesis of membrane-bound non-specific acid phosphatase, strictly regulated by phosphate, and its properties suggest that this bacterium has a potential biotechnological application to solubilize phosphate in soils with low levels of this element, for specific crops.
Tiago Henrique
TH
Rombola
Eliamar Aparecida Nascimbem
EA
Pedrinho
Eliana Gertrudes
EG
de Macedo Lemos
Adriano Marques
AM
Gonçalves
Luiz Flávio José
LF
dos Santos
Faculdade de Ciências Agrárias e Veterinárias (FCAV), UNESP - Univ Estadual Paulista, Câmpus de Jaboticabal, Departamento de Tecnologia, Laboratório de Enzimologia Aplicada, Jaboticabal, SP, Brazil. jpizauro@fcav.unesp.br.
João Martins
JM
Pizauro
D000135:Acid Phosphatase / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D042725:Burkholderia gladioli / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009596:Nitrophenols / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000737:chemistry; D010758:Phosphorus / Q000378:metabolism / Q000494:pharmacology; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D010944:Plants / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D013379:Substrate Specificity; D013559:Symbiosis
D001426:Bacterial Proteins; D008565:Membrane Proteins; D009596:Nitrophenols; D009943:Organophosphorus Compounds; D012336:RNA, Ribosomal, 16S; D010758:Phosphorus; C008644:nitrophenylphosphate; D000135:Acid Phosphatase