Haas Amy L, Laun Nathan P, Begley Tadhg P
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
Bioorg Chem. 2005 Aug;33(4):338-44. doi: 10.1016/j.bioorg.2005.04.001.
Saccharomyces cerevisiae Thi20 is a fusion protein with homology to Bacillus subtilis ThiD and TenA. The N-terminus of Thi20 has significant sequence homology to B. subtilis ThiD, while the C-terminus has homology to B. subtilis TenA. Incubation of Thi20 with thiamin reveals that it has thiaminase II activity, in addition, incubation of Thi20 with HMP (4-amino-2-methyl-5-hydroxymethylpyrimidine) and ATP reveals that it has HMP kinase and HMP-P (4-amino-2-methyl-5-hydroxymethylpyrimidine phosphate) kinase activity. This demonstrates that Thi20 is a trifunctional protein with thiamin biosynthetic and degradative activity.
酿酒酵母Thi20是一种与枯草芽孢杆菌ThiD和TenA具有同源性的融合蛋白。Thi20的N端与枯草芽孢杆菌ThiD具有显著的序列同源性，而C端与枯草芽孢杆菌TenA具有同源性。Thi20与硫胺素一起孵育表明它具有硫胺素酶II活性，此外，Thi20与HMP（4-氨基-2-甲基-5-羟甲基嘧啶）和ATP一起孵育表明它具有HMP激酶和HMP-P（4-氨基-2-甲基-5-羟甲基嘧啶磷酸）激酶活性。这表明Thi20是一种具有硫胺素生物合成和降解活性的三功能蛋白。
