Species: Thermus thermophilus
Subunit composition of L-asparaginase = [L-asparaginase subunit]6
The relative molecular mass of native L-asparaginase from Thermus thermophilus was determined by gel filtration chromatography [Pritsa01].
L-Asparaginase has been characterized from diverse sources, including bacteria, archaea [Yao05], fungi [Sinclair94, Kil95, Raha90], and ciliates [Tsavdaridis94]. It has also been characterized from the liver and serum of guinea pigs [Zhang95c]. The enzyme has anti-tumor activity and purified L-asparaginase from Escherichia coli and Dickeya chrysanthemi have been used clinically to treat lymphoblastic leukemia and lymphosarcoma (in [Kotzia05]). The enzyme from some species contains glutaminase activity, believed to cause clinical side-effects. Enzyme preparations from species with decreased glutaminase activity, such as Pectobacterium carotovorum (previously known as Erwinia carotovora) have been characterized as potential therapeutics [Kotzia05].
L-asparaginases are L-amidohydrolases, assigned to two classes based on substrate specificity: those that primarily hydrolyze L-asparagine; and those that hydrolyze L-glutamine and L-asparagine with equal efficiency (in [Aghaiypour01]).
It has been reported that all bacterial L-asparaginases are homotetramers (in [Aghaiypour01] and in [Kotzia05]), although the enzyme from Thermus thermophilus was reported to be a homohexamer [Pritsa01]. Crystal structures have been solved for at least five bacterial L-asparaginases (in [Aghaiypour01a]). The reaction mechanism has been described as a two-step ping-pong mechanism (in [Aghaiypour01]).
The antitumor activity of Thermus thermophilus L-asparaginase has been investigated. The enzyme did not show glutaminase activity
The relative molecular mass of the L-asparaginase subunit was determined by SDS-PAGE [Pritsa01].
Molecular Weight of Polypeptide: 33 kD (experimental) [Pritsa01]
Molecular Weight of Multimer: 200 kD (experimental) [Pritsa01]
pI: 6.0 [Pritsa01]
Enzymatic reaction of: L-asparaginase
EC Number: 126.96.36.199L-asparagine + H2O → L-aspartate + ammonium
The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.
The reaction is physiologically favored in the direction shown.
In Pathways: L-asparagine degradation I
This thermostable enzyme from Thermus thermophilus did not show glutaminase activity [Pritsa01].
pH(opt): 9.2 [Pritsa01]
Aghaiypour01: Aghaiypour K, Wlodawer A, Lubkowski J (2001). "Structural basis for the activity and substrate specificity of Erwinia chrysanthemi L-asparaginase." Biochemistry 40(19);5655-64. PMID: 11341830
Pritsa01: Pritsa AA, Kyriakidis DA (2001). "L-asparaginase of Thermus thermophilus: purification, properties and identification of essential amino acids for its catalytic activity." Mol Cell Biochem 216(1-2);93-101. PMID: 11216870
Yao05: Yao M, Yasutake Y, Morita H, Tanaka I (2005). "Structure of the type I L-asparaginase from the hyperthermophilic archaeon Pyrococcus horikoshii at 2.16 angstroms resolution." Acta Crystallogr D Biol Crystallogr 61(Pt 3);294-301. PMID: 15735339
Zhang95c: Zhang N, Clarke F, Di Trapani G, Keough D, Beacham I (1995). "Guinea pig serum L-asparaginase: purification, and immunological relationship to liver L-asparaginase and serum L-asparaginases in other mammals." Comp Biochem Physiol B Biochem Mol Biol 112(4);607-12. PMID: 8590375
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