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 [Zhang95a]. 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 [Pritsa01a].
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: 18.104.22.168
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, 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
Zhang95a: 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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