PURIFICATION AND CHARACTERIZATION OF 2 PHYTASES FROM ESCHERICHIA-COLI
PURIFICATION AND CHARACTERIZATION OF 2 PHYTASES FROM ESCHERICHIA-COLI
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DOI：
10.1006/abbi.1993.1261
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发表时间：
1993-05-15
影响因子：
3.9
通讯作者：
JANY, KD
中科院分区：
文献类型：
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作者：
GREINER, R;KONIETZNY, U;JANY, KD
两个胞外植酸酶，称为P1和P2，纯化了约16,500倍，其纯度分别为7%和18%。这些酶表现为单体蛋白质，分子质量约为42 kDa。由于回收的量有限，只测定了其中一个植酸酶的氨基末端序列。这两种酶都是植酸的专一性酶，对所测试的其他磷酸酯几乎没有或几乎没有活性。在pH为4.5时，植酸钠和对硝基苯基磷酸酯的水解酶动力学参数分别为CAT/KM478×105S−1M−1和0.6·105S−1M−1。P2是植酸的水解酶，因此，该酶是一种6-植酸酶。纯化的植酸酶P2的化学性质和动力学性质表明，它与达萨等人描述的一种酶具有相同的性质。(1982，J.Biol.化学257,6669-6676)作为pH 2.5的酸性磷酸酶。考虑到动力学参数，最好将该酶命名为植酸酶。
Two periplasmatic phytases, called P1 and P2, were purified about 16,500-fold to an apparent homogeneity with a recovery of 7 and 18%, respectively. The enzymes behave as monomeric proteins with molecular masses of about 42 kDa. Because of the limited amounts recovered, the amino terminal sequence of only one of the phytases was determined. Both enzymes are very specific for phytate and have little or no activity on other phosphate esters tested. The kinetic parameters for the hydrolysis of Na-phytate andp-nitrophenyl phosphate arekcat/KM478 ×105s−1M−1and 0.6 · 105s−1M−1at pH 4.5. The hydrolysis pathway for phytate was elucidated for P2; consequently, this enzyme is a 6-phytase. The chemical and kinetic properties of the purified phytase P2 points to an identity with an enzyme described by Dassaet al. (1982,J. Biol. Chem.257, 6669-6676) as a pH 2.5 acid phosphatase. Because of the kinetic parameters it would be better to denote this enzyme as a phytase.