Static and dynamic half-life and lifetime molecular turnover of enzymes.

The static half-life of an enzyme is the half-life of a free enzyme not working without substrate and the dynamic half-life is that of an active enzyme working with plenty amount of substrate. These two half-lives were measured and compared for glucoamylase (GA) and β-galactosidase (BG). The dynamic half-life was much longer than the static half-life by one to three orders of magnitude for both enzymes.

Mutation analysis of vinyl carbamate or urethane induced lung tumors in rasH2 transgenic mice.

Previous studies showed that significant differences in mutation frequency of the human c-Ha-ras transgene between vinyl carbamate (VC)- and ethyl carbamate (urethane)-induced lung tumors were observed in rasH2 mice. It remains unclear why the point mutation frequency is extremely low in VC-induced lung tumors, although this compound is much more carcinogenic than urethane. In this study, we examined the somatic point mutations of the transgene at the RNA level in VC- and urethane-induced lung tumors of rasH2 mice.

Genotyping the mouse severe combined immunodeficiency mutation using the polymerase chain reaction with confronting two-pair primers (PCR-CTPP).

An allele specific polymerase chain reaction with confronting two-pair primers (PCR-CTPP) was developed as an assay for genotyping the mouse Prkdcscid gene mutation (former name scid). The reverse primer (WR) was designed to include the antisense nucleotide (A) specific for the wild type allele at the 3' end with the counterpart forward primer (F) upstream. The other forward primer (MF) was designed to include the sense nucleotide (A) specific for the Prkdcscid mutation at the 3' end with the other counterpart reverse primer (R) downstream.

Transgene stability and features of rasH2 mice as an animal model for short-term carcinogenicity testing.

The transgenic mouse rasH2 line, in which the mouse carries the human c-Ha-ras gene under the control of its own enhancer and promoter, has been proposed as one of the alternative short-term models for carcinogenicity testing. To apply this purpose, we have produced a genetically homogeneous population as C57BL/6JJic-TgN(RASH2) (Tg-rasH2) by continuous backcrossing. In this study, we examined the transgene stability between different generations and the detailed transgene architecture of the integrated human c-Ha-ras gene.