Highly Sensitive Microplate-Elisa for Angiotensin I Using 3,3′,5,5′-Tetramethylbenzidine

Abstract
A microplate-ELISA was established for angiotensin (Ang) I using Ang I -peroxidase conjugate, antiAng I antibodies which could distinguish Ang I from Ang II and Ang III, and 3,3′,5,5′-tetramethylbenzidine. Ang I could be quantified in amounts as low as 1 pg by the spectrophotometric method. The present assay system was the most sensitive and rapid in all Ang I assay systems described so far. The assay system was applicable to determination of Ang I concentration in human plasma and abdominal fluid.