Spivak D A, Hoffman T Z, Moore A H, Taylor M J, Janda K D
The Scripps Research Institute, Department of Chemistry and The Skaggs Institute for Chemical Biology, La Jolla, CA 92037, USA.
Bioorg Med Chem. 1999 Jun;7(6):1145-50. doi: 10.1016/s0968-0896(99)00026-7.
A new amine-oxide hapten was employed as an antigen, producing seven monoclonal antibodies (mAbs) from a panel of 20 that catalyzed paraoxon hydrolysis. The current hapten design differs from that previously described in that the molecule is inherently more flexible than its constrained predecessor. One of the seven antibody catalysts, mAb 1H9, showed the highest activity and was selected for detailed study. At pH = 8.77, the catalytic hydrolysis of paraoxon by mAb 1H9 followed Michaelis Menten kinetics affording a k(cat) = 3.73 x 10(-4) min(-1) and a Km = 1.12 mM with a rate acceleration k(cat)/k(uncat) = 56. The hapten was found to be a competitive inhibitor of antibody-catalyzed paraoxon hydrolysis with a Ki = 0.54 mM. A comparison of both the number and proficiency of antibody catalysts obtained when utilizing a flexible versus constrained hapten indicates that, for paraoxon hydrolysis, constrained haptens elicit superior catalysts, suggesting that further development should begin with the use of constrained haptens in producing more proficient antibody catalysts for paraoxon hydrolysis.
一种新型氧化胺半抗原被用作抗原，从20种能催化对氧磷水解的单克隆抗体（mAb）中产生了7种单克隆抗体。目前的半抗原设计与先前描述的不同，因为该分子本质上比其受限制的前身更具柔韧性。七种抗体催化剂之一，即单克隆抗体1H9，表现出最高活性，并被选作详细研究对象。在pH = 8.77时，单克隆抗体1H9催化对氧磷水解遵循米氏动力学，得到的催化常数k(cat) = 3.73×10⁻⁴ min⁻¹，米氏常数Km = 1.12 mM，速率加速比k(cat)/k(uncat) = 56。发现该半抗原是抗体催化对氧磷水解的竞争性抑制剂，抑制常数Ki = 0.54 mM。比较使用柔性半抗原和受限制半抗原时获得的抗体催化剂的数量和效能表明，对于对氧磷水解，受限制半抗原能产生更优异的催化剂，这表明进一步的研发应从使用受限制半抗原开始，以生产更高效的对氧磷水解抗体催化剂。
