ABSTRACT
Enzymes are proteins which have catalytic properties that include specific activation of their respective substrates. Much emphasis is placed on the application of plasma enzymes as markers of organ damage, with many enzymes used in toxicological studies to measure cellular injury, enzyme induction, activation or inhibition of enzymes. The distribution of enzymes in different tissues varies between species, and therefore influences their diagnostic value in particular species (Clampitt and Hart, 1978; Keller, 1981; Lindena et al., 1986; Milne and Doxey, 1987; Davy et al., 1988). The tissue distribution of an enzyme can also be affected by age and sex, and it may vary in the different cell types within an organ, e.g. kidney and liver (Braun et al., 1983). Caution must be exercised when interpreting data on tissue enzyme distribution when a single extraction and assay system has been used, as this does not allow for the variable requirements for optimizing enzyme extraction and for the measurement of the enzyme.
