Different expressions for enzyme activities in organs of rat. Application to aspartate transaminase, glutamate dehydrogenase and AMP-deaminase

Abstract

The widely used activity expressions for enzyme levels in tissues are discussed: microkatals per unit of tissue weight, protein weight, and DNA weight. The expression of microkatals present in a definite organ in reference to a standard animal weight, 100 g in the case of rat, is also used. The different expressions are applied to aspartate transaminase, glutamate dehydrogenase and AMP deaminase activities in liver, hind leg striated muscle and kidneys in rat. The conclusion is reached that measurements of enzyme activity in tissues should be expressed in more than one form, as the information drawn from one could differ substantially from that obtained from other, giving artifactual views of the metabolic role played by the enzyme in a given tissue.