Reference

Interaction of 4-nitroquinoline-1-oxide and methyl methanesulfonate on DNA strand breaks and excision repair in mammalian cells

Interaction of 4-nitroquinoline-1-oxide and methyl methanesulfonate on DNA strand breaks and excision repair in mammalian cells. Park, Sang Dai; Park, Jong Kun; Lee, Jung Sup (Dep. Zool., Seoul Natl. Univ., Seoul 151, S. Korea). Korean J. Genet., 6(1), 15-28 (English) 1984. CODEN: KJGEDG. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) The rates of unscheduled DNA synthesis induced by the combined treatment with 4-NQO [56-57-5] and MeSO3Me (MMS) [66-27-3] in CHO cells were less than the sum of those induced by each agent independently. These results were marked in MMS posttreatment, but these initial discrepancies disappeared as time elapsed with fluctuations at 1 h. The alk. elution rates in the combined treatment with 4-NQO and MMS were higher than those for single 4-NQO treatment, but were lower than those for MMS treatment. These abnormal profiles were reversed by incubation with proteinase K [39450-01-6] or treatment with hydroxyurea [127-07-1] and ara-C [147-94-4]. However, the amts. of DNA single strand breaks induced by MMS posttreatment were less than those induced by MMS pretreatment which were almost additive. The strand break frequencies in the MMS posttreatment were lower than those in MMS treatment alone. MMS may have common steps in the repair of 4-NQO-induced DNA damage but exert an inhibitory effect on 4-NQO-induced DNA repair in the MMS posttreatment.

Albomycins, I

Albomycins, I. Enzymic cleavage of the deferri form of albomycins d1 and d2. Benz, Guenter (Forschungslab., Bayer A.-G., Wuppertal D-5600/1, Fed. Rep. Ger.). Liebigs Ann. Chem., (8), 1399-407 (German) 1984. CODEN: LACHDL. ISSN: 0170-2041. DOCUMENT TYPE: Journal CA Section: 16 (Fermentation and Bioindustrial Chemistry) Enzymic hydrolyses of albomycin d2 (I) [34755-52-7] were attempted with 23 enzymes or enzyme mixts. I and albomycin d1 were cleaved with leucine aminopeptidase [9001-61-0] (microsomal, hog kidney), subtilisin [9014-01-1], aminoacylase I [9012-37-7], b-lactamase [9073-60-3], proteinase K [39450-01-6], and pronase E [9036-06-0] to give serine-contg. nucleosides. With microsomal leucine aminopeptidase a further reaction yields serine-free nucleosides. A hydroxamic acid was also isolated.