RESUMO
A DNA-linked polymer micelle was prepared through a phase transition of an amphiphilic copolymer consisting of single-stranded DNA as the hydrophilic part and thermo-responsive poly(N-isopropylacryl-amide) as the hydrophobic part. Duplex formation on the surface of micelle decreased the colloidal stability, whereas a terminal single-base mismatch at the interface between the DNA shell and the disperse medium increased the colloidal stability. Based on this change, we successfully detected base pairing of 7,8-dihydro-8-oxo-2'-deoxyguanine with adenine. This method will be useful for discovering a Watson-Crick or non Watson-Crick base pair of an unknown oxidative-damaged base with each four canonical one.
Assuntos
Acrilamidas/química , Dano ao DNA , DNA/química , Desoxiguanosina/análogos & derivados , Polímeros/química , 8-Hidroxi-2'-Desoxiguanosina , Resinas Acrílicas , Adenina/química , Pareamento de Bases , Coloides , DNA de Cadeia Simples/química , Desoxiguanosina/química , Micelas , OxirreduçãoRESUMO
Sulfhydryl groups of glucose oxidase (GOD) were reacted with maleimide groups of polymaleimidostyrene (PMS) which was coated onto the porous carbon sheet, and the carbon sheet immobilized by GOD was combined with an oxygen electrode to fabricate a glucose sensor. The activity of thiolated GOD immobilized to PMS is much larger than that of native GOD immobilized to PMS. The good linear relationship of glucose and oxygen current response was obtained in a concentration range from 0.1 to 2 mM and upper limit of linear range was found to be 3.0 mM. The immobilized GOD activity is highly dependent on pH at immobilization and the maximum activity was obtained at pH 5.5, probably because the SH groups of GOD that are indispensable for generation of enzyme activity is not exposed at this pH. It was found that PMS is very effective reagent to immobilize enzyme strongly via covalent bond, because high density of maleimide groups of PMS can catch not only exposed SH groups but also buried SH groups.
