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An essential tryptophan residue of green crab (Syclla Serrata) alkaline phosphatase
Author(s) -
Zheng WenZhu,
Chen QingXi,
Zhao Hong,
Zhang Zhe,
Zhang Wei,
Zhou HaiMeng
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700202011
Subject(s) - tryptophan , alkaline phosphatase , chemistry , residue (chemistry) , scylla serrata , enzyme , fluorescence , biochemistry , enzyme assay , biology , ecology , amino acid , physics , quantum mechanics
The tryptothan residues in green crab (scylla serrata) alkaline phosphatase (EC 3.1.3.1) have been modified by N‐bromosuccinimide (NBS). The modification of five tryptophan residues leads to complete loss of enzymatic activity. With the increase of NBS concentration, both the absorption at 278 nm and the fluorescence emission intensity at 335 nm of the modified enzyme decreased markedly indicating the modification of tryptophan residues. Quantitative treatment of the data (Tsou, Sci. Sinica 1962, 11, 1535‐1558) shows that among the tryptophan residues modified, one is essential for its catalytic activity. The presence of the substrate markedly protects the modification of tryptophan residues as well as the inactivation, suggesting that the essential tryptophan residue is situated at the active site of this enzyme.