Application | Comment | Organism |
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medicine | modification of thiaminase with linear chain methox polyethylene glycol of 5 kDa eliminates cytotoxic activity in all cell lines tested. Both native thiaminase and 5k-PEGylated thiaminase efficiently depletes thiamine from cell culture medium, and both can use intracellular phosphorylated thiamine as substrates. Native enzyme more effectively depletes thiamine and thiamine diphosphate in RS4 leukemia cell cytosol, and native thiaminase depresses cellular respiration, whereas PEGylated thiaminase does not. Despite the lack of in vitro cytotoxicity, PEGylation markedly increases the in vivo toxicity of the enzyme. The half-life of native thiaminase is 1.5 h compared with 34.4 h for the 5k-PEGylated enzyme. Serum thiamine levels are depleted by both native and 5k-PEGylated enzyme. Despite superior pharmacokinetics, 5k-PEGylated thiaminase shows no antitumor effect against an RS4 leukemia xenograft, in contrast to native thiaminase | Paenibacillus thiaminolyticus |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Paenibacillus thiaminolyticus | - |
isoform thiaminase I | - |