Automated stopped-flow kinetic analysis of serum enzymes.

Abstract

An instrument which permits the automated determination of serum lactate dehydrogenase, serum glutamic oxalacetic transaminase, and serum glutamic pyruvic transaminase by the standard kinetic methods at 340 nm. is described. As many as 120 sera can be loaded into the sampler wheels at one time and the change in absorbance with time for all the samples is recorded automatically without further handling of the specimens or instrument by the technologist. The work output is 45 determinations per hour, with the change in absorbance being measured for 2 minutes for each sample. The system is modular and requires two samplers, a pump, a thermostating bath, an ultraviolet spectrophotometer with recorder, and a timing device which can be assembled from readily available parts. The instrument has been in constant use in this laboratory since December 1970. There is excellent agreement between the automated method described here and the standard manual ultraviolet-kinetic methods. The automated method permits pre-incubation with nicotinamide adenine dinucleotide to destroy endogenous serum keto acids and allows for the induction period in the determination of serum glutamic oxalacetic transaminase and serum glutamic pyruvic transaminase.