PLASMA PROTEINS AS EARLY BIOMARKERS OF EXPOSURE TO CARCINOGENIC AROMATIC AMINES

这个项目的目标是评估血浆蛋白的变化。 作为接触致癌芳香胺的早期生物标志物。 用双向凝胶电泳法(2DG)研究了大豆蛋白的分离和鉴定。 几种已知膀胱癌致癌物对犬血浆的影响 4-氨基联苯(4-ABP)和2-萘胺(2-NA)。3-氨基联苯 (3-ABP)和1-萘胺(I-NA)，均被认为是 非致癌物质，作为对照。这项研究的目的是： (1)确定血浆蛋白的表观缺失 是4-ABP特异的；(2)测量抑制中的时间进程 在给药过程中的主要多肽以及它们在 恢复期；(3)通过微测序直接确定 凝胶，受影响斑点的生物化学特征。结果是 表明抑制作用仅限于4-ABP、3-ABP、2-NA和 1-NA在12周内没有引起2DG模式的明显变化 给药期。4-ABP导致戏剧性地抑制了两组 斑点。其中一个表观分子量为32.5kD，等电点为5.8-6.0。 被鉴定为结合珠蛋白的B链。此斑点消失后 大约两周的治疗，停止给药后恢复缓慢。 结合珠蛋白的功能是与游离的血红蛋白结合，并将其从 血液流动。由于4-ABP会引起溶血， 结合珠蛋白很容易解释。在第二组斑点中，一颗兆瓦65 KD，等电点6.5-6.6，比结合珠蛋白消失得快得多，并且 恢复得更快。这种蛋白质的强度约为 结合珠蛋白和似乎被阻断，就像N-末端微测序 一直不成功。目前正在进行工作，以获得内部 对这种多肽进行测序，以便对其进行鉴定。

The objective of this project is to evaluate changes in plasma proteins as an early biomarker of exposure to carcinogenic aromatic amines. Two-dimensional gel electrophoresis (2DG) has been used to study the changes induced in dog plasma by the known urinary bladder carcinogens 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA). 3-Aminobiphenyl (3-ABP) and 1-napthylamine (I-NA), both considered to be non-carcinogenic, were used as controls. The purpose of this study was: (1) to determine whether or not the apparent deletions on plasma proteins are specific to 4-ABP; (2) to measure the time course in the suppression of the major polypeptides during dosing and their re-synthesis during a recovery period; and (3) to determine, by microsequencing directly off the gels, the biochemical identity of the affected spots. The results indicate that the suppression is limited to 4-ABP, with 3-ABP, 2-NA and 1-NA causing no discernible change in the 2DG patterns over a 12 week dosing period. The 4-ABP caused dramatic suppression of two sets of spots. One of apparent molecular weight 32.5 kD, and pI 5.8-6.0, was identified to be the B chain of haptoglobin. This spot disappears after about two weeks of treatment and recovers slowly after dosing stops. Haptoglobin functions to bind with free hemoglobin and purge it from the blood stream. Since 4-ABP causes hemolysis, the disappearance of the haptoglobin is readily explained. Among the second set of spots, a MW 65 kD, pI 6.5-6.6 peptide, disappears much faster than the haptoglobin, and recovers more quickly. The protein is about one-fifth the intensity of haptoglobin and appears to be blocked, as N-terminal microsequencing has been unsuccessful. Work is currently underway to obtain an internal sequence of this polypeptide in order to identify it.