ENZYME PATTERNS IN HUMAN TISSUES. I. METHODS FOR THE DETERMINATION OF GLYCOLYTIC ENZYMES.

TLDR

The study aims to develop reliable methods for comparing enzyme patterns in malignant and nonmalignant human tissues. The authors describe a unified, NAD‑dependent assay protocol that measures all glycolytic and related enzymes in crude tissue homogenates, validated with rat tissues for precision and enzyme stability at –20 °C. The method enables direct comparison of enzyme activities and reveals potential metabolic rates, rate‑limiting steps, and alternative pathways, though it does not reflect in vivo rates.

Abstract

Summary The prospective aim of these studies is the development of consonant procedures for the determination of comparative enzyme patterns in human malignant and nonmalignant tissues. Based on the well established principle of using nicotinamide adenine dinucleotides to follow reaction rates, improved methods and a unified program for the determination of all the glycolytic and some related enzymes in crude tissue homogenates have been described. With rat tissues used as models, the precision of the measurements and the stability of the enzymes to storage in the intact tissues at -20°C. have been established. The consonant methodology permits direct comparison of the activities of all the enzymes. Although such enzyme patterns cannot yield information on the actual rates of metabolic processes in vivo, they do give information on the potential rates of metabolite flow, the steps in an enzymic reaction chain that are likely to be rate limiting, and the potential for alternate metabolic pathways.