Toering S J, Gentile G J, Gentile J M
Biology Department, Hope College, Holland, MI 49423, USA.
Mutat Res. 1996 Dec 12;361(2-3):81-7. doi: 10.1016/s0165-1161(96)90242-3.
Aromatic amines are activated into mutagens by both animal and plant systems. For plant-activated aromatic amines an important step in this process involves peroxidase enzymes. 4-nitro-o-phenylenediamine (NOP) is a well known direct-acting mutagen that can be enhanced in mutagenic potency by intact plant cells and also by isolated peroxidase enzymes. This activation process is inhibited by several different chemical agents including potassium cyanide (KCn), a known peroxidase inhibitor, and (+)-catechin. In our laboratory both KCn and (+)-catechin inhibited peroxidase-mediated NOP activation into a Salmonella mutagen. However, while KCn demonstrated strong peroxidase enzyme inhibition (as measured biochemically), (+)-catechin showed only minimal inhibition of peroxidase. Experiments comparing NOP direct and plant-activated mutagenic activity to different Salmonella strains (in the presence and absence of (+)-catechin) suggest that (+)-catechin may inhibit the mutagenic process by limiting O-acetyltransferase (OAT) activity in Salmonella. OAT activity in Salmonella is a required process for mutations to be induced following treatment with NOP and other aromatic amines.
芳香胺可被动物和植物系统激活成为诱变剂。对于植物激活的芳香胺，这一过程中的一个重要步骤涉及过氧化物酶。4-硝基邻苯二胺（NOP）是一种众所周知的直接作用诱变剂，完整的植物细胞以及分离出的过氧化物酶均可增强其诱变效力。包括氰化钾（KCn，一种已知的过氧化物酶抑制剂）和（+）-儿茶素在内的几种不同化学试剂可抑制这一激活过程。在我们实验室，KCn和（+）-儿茶素均抑制过氧化物酶介导的NOP激活成为沙门氏菌诱变剂。然而，虽然KCn表现出强烈的过氧化物酶抑制作用（通过生化方法测定），但（+）-儿茶素对过氧化物酶的抑制作用却很微弱。将NOP直接和植物激活的诱变活性与不同沙门氏菌菌株进行比较的实验（在有和没有（+）-儿茶素的情况下）表明，（+）-儿茶素可能通过限制沙门氏菌中的O-乙酰转移酶（OAT）活性来抑制诱变过程。沙门氏菌中的OAT活性是在用NOP和其他芳香胺处理后诱导突变所必需的过程。
