Partial purification and characterization of an endo-alpha-N-acetylgalactosaminidase from the culture of medium of Diplococcus pneumoniae.
Partial purification and characterization of an endo-alpha-N-acetylgalactosaminidase from the culture of medium of Diplococcus pneumoniae.
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DOI：
10.1093/oxfordjournals.jbchem.a131240
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发表时间：
1976-07
影响因子：
2.7
通讯作者：
Y. Endo;A. Kobata
中科院分区：
文献类型：
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作者：
Y. Endo;A. Kobata
肺炎双球菌培养基具有酶活性，可将人红细胞膜糖蛋白中的Galbeta1导联体裂解为3GalNAc。通过硫酸铵分馏法、Sephadex G-200柱凝胶过滤、DEAE a -25 Sephadex层析纯化酶180倍。纯化后的酶从糖肽和糖蛋白中释放Galbeta1导致3GalNAc，其中Galbeta1导致3galnaalpha1导致Ser和Thr部分。该酶的最适pH为6.0。利用胰蛋白酶消化人红细胞膜糖蛋白得到的糖肽作为底物，得到Km为0.20 mM（根据Galbeta1导致3GalNAc残基的量）。到目前为止，该酶似乎对Galbeta1导致3GalNAcalpha1导致Ser和Thr结构具有严格的特异性，因为没有比三糖更大的低聚糖从猪颌下粘蛋白中释放出来。
The culture medium of Diplococcus pneumoniae contains enzymic activity that cleaves Galbeta1 leads to 3GalNAc from desialized human erythrocyte membrane glycoprotein. The enzyme was purified 180-fold by ammonium sulfate fractionation, gel filtration through a Sephadex G-200 column, and DEAE A-25 Sephadex chromatography. The purified enzyme liberates Galbeta1 leads to 3GalNAc from glycopeptides and glycoproteins with Galbeta1 leads to 3GalNAcalpha1 leads to Ser and Thr moieties. The optimum pH of this enzyme is 6.0. Using glycopeptides obtained by trypsin digestion of human erythrocyte membrane glycoprotein as a substrate, a Km of 0.20 mM (on the basis of the amount of Galbeta1 leads to 3GalNAc residues) was obtained. So far, the enzyme appears to have a strict specificity for Galbeta1 leads to 3GalNAcalpha1 leads to Ser and Thr structures, because no oligosaccharides larger than trisaccharides were liberated from porcine submaxillary mucin.