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At least 217 records · Page 12Linked to original sources
PubMed1983

Enzyme-induced aziridine formation by rat liver microsomes.

The metabolic reaction of 2-chloroethylaminobenzoquinone derivatives with rat liver microsomes was studied. In buffer solution containing cellular macromolecules such as DNA or protein, 2-chloroethylaminobenzoquinones were usually stable and could be recovered quantitatively after an appropriate period of incubation. However, in microsomal solution, they were gradually converted into aziridinobenzoquinones via elimination of hydrogen chloride by NADPH-dependent enzyme action. Based on the study of the enzymatic cyclization reaction of 4-chlorobutylaminonaphthoquinone, we concluded that the hydroquinone derivative is an important intermediate for aziridine formation.

Animals↗
PubMed1983

Enzyme-induced aziridine formation by isolated hepatocytes.

The metabolism of 2-bromoethylaminonaphthoquinone in hepatocytes isolated from rats was studied. This compound was chemically inert in the reaction system used. However, in buffer solution containing isolated hepatocytes, it was gradually converted into aziridinylnaphthoquinone. Under the same reaction conditions, 4-chlorobutylaminonaphthoquinone also gave the cyclization products, pyrrolidinylnaphthoquinone. Cellular GSH decreased in both reactions.

Animals↗
PubMed1985

Diaziquone as a potential agent for photoirradiation therapy: formation of the semiquinone and hydroxyl radicals by visible light.

When diaziquone was irradiated with 500 nm visible light, hydroxyl free radicals as well as the diaziquone semiquinone were produced. The diaziquone semiquinone is a stable free radical that exhibits a characteristic 5-line electron spin resonance (ESR) spectrum. Since hydroxyl free radicals are short lived, and not observable by conventional ESR, the nitrone spin trap 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) was used to convert hydroxyl radicals into longer lived ESR detectable spin adducts. The formation of hydroxyl radicals was further confirmed by investigating reactions in which hydroxyl radical scavangers, sodium formate and dimethylsulfoxide, compete with the spin traps DMPO or POBN (alpha-(4-Pyridyl-1-oxide)-N- tert-butylnitrone) for hydroxyl free radicals. The products of these scavenging reactions were also trapped with DMPO or POBN. If drug free radicals and hydroxyl free radicals are important in the activity of quinone-containing antitumor agents, AZQ may have a potential in photoirradiation therapy or photodynamic therapy.

Aziridines↗
PubMed1986

CB 1954 (2,4-dinitro-5-aziridinyl benzamide) becomes a DNA interstrand crosslinking agent in Walker tumour cells.

Walker tumour cells were shown to be uniquely sensitive to CB 1954 when compared with other cells in vitro. CB 1954 forms DNA-DNA interstrand crosslinks in a time-dependent manner in Walker tumour but not Chinese hamster cells. The absence of interstrand crosslinks in hamster cells was not due to a lack of uptake of drug but rather to a failure to convert (probably by bioreduction) CB 1954 to the required reactive difunctional intermediate.

Animals↗
PubMed1989

Conduritol aziridine: a new mechanism-based glucosidase inactivator.

A new mechanism-based glucosidase inactivator, conduritol aziridine (1,2-dideoxy-1,2-epimino-myo-inositol), has been synthesised from myo-inositol. This aziridine inactivates both the beta-glucosidase from Alcaligenes faecalis and the alpha-glucosidase from yeast according to the expected pseudo-first order kinetics. Inactivation constants measured are Ki = 3.0mM, ki = 0.077 min-1 for the beta-glucosidase, and Ki = 9.5mM, ki = 0.39 min-1 for the alpha-glucosidase. Evidence for irreversible inactivation is provided by the lack of reactivation upon dilution of inactivated enzyme into buffer containing substrate.

Alcaligenes↗