30 BACTERIAL ENZYMES 



under pressure has been devised by Booth and Green.^ A 

 simpler mill has recently been produced in which a steel ball 

 runs in a closely fitting channel in a steel bowl, the whole 

 being immersed in solid COg ; the combined effect of pressure 

 and freezing accomplishing disintegration of the cells. 



4. Disintegration by friction between fine hard particles. 

 Werkman and his colleagues^ first showed that thick pastes 

 of bacterial cells can be disintegrated by grinding with finely 

 powdered glass in a mortar. They later evolved a mechanical 

 mortar to deal with large quantities of organism. Other 

 workers have found that powders of carborundum or alumina 

 are as effective as glass. 



5. Disintegration by vibration. Exposure of cell suspen- 

 sions to supersonic vibration of a certain range of frequency 

 results in very effective breakdown of the cell structure, in 

 fact, care has to be taken to prevent breakdown of the enzyme 

 structures themselves. Vibration of lower frequency is often 

 effective {i.e. sonic vibration of 50-60 cycles/sec.) but the 

 efficiency is usually increased by addition of small glass beads 

 or carborundum particles to the cell material.^ 



6. Specific treatment can be applied to certain organisms. 

 Thus the enzymes of Micrococcus lysodeikticus and some strains 

 of Staphylococcus can be liberated after disintegration of the 

 cell-wall with preparations of lysozyme. 



THE NATURE OF ENZYMES 



Such studies often lead to knowledge concerning the nature 

 of the enzymes concerned and it has been found that although 

 all enzymes have the properties of proteins, many of them 

 consist of two parts, one protein in nature and the other, 

 called the prosthetic group, of a simpler non-protein nature. 

 Prosthetic groups can often be detached from the protein 

 moiety — in which case the enzymatic activity ceases — and 

 their structure determined. The link between the, prosthetic 



1 Booth and Green, Biochem, J., 1938, 32, 855. 



2 Werkman et al, J. BacL, 1945, 49, 595. 



3 Curran and Evans, J. Bad., 1942, 43, 125. 



