Treatment of samples for enzyme assay

Studies of the enzyme content of cells frequently involve the use of coarse tissue samples of either animal or plant origin. In such cases some preliminary dissection of the tissue may be necessary to isolate the relevant tissue components and remove unwanted structural material such as collagen, cellulose, etc., before moving on to the more critical disruption of the cells. Sometimes it is possible to use the technique of tissue culture to provide pure cell preparations for subsequent studies. 

Tissue culture, more frequently used as cell culture, enables animal and plant cells to be cultured in large numbers by techniques comparable to those used in microbiology but, because of the fragile nature of the cells, does require special cultural conditions. The culture media used must supply all the essential factors for growth, such as a wide range of amino acids, nucleotides, enzyme co-factors as well as indeterminate factors that can only be supplied in special products, e.g. foetal bovine serum. The environmental conditions must be carefully controlled, particularly pH, and this is frequently maintained by culturing in a bicarbonate buffer system and a carbon dioxide saturated atmosphere. 

The build-up of waste products inhibits growth and it is necessary to change the culture medium at regular intervals, usually every few days. As with all cell culture techniques, asepsis is essential but very difficult to maintain. Antibiotics may therefore be incorporated into the culture media to assist in maintaining sterility. 

All samples must be stored appropriately to minimize the loss of activity due to protein denaturation, lack of stabilizers or presence of inhibitors. Optimal storage conditions will vary for different enzymes and the nature of the sample, blood, tissue, etc. Such information would be sought from specialist textbooks. 

Gross homogenization of tissues may be achieved with one of the high 

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