MUCOLYTIC ENZYMES 



prepared, pure lysozyme has a negligible avidin activity. It was found 

 that biotin (10 7) increased the activity of our lysozyme preparation 

 (approximately 1 7) up to 500-fold. Lysis at such dilutions of lyso- 

 zyme had never been observed before. However, the activation was 

 shown by only a limited number of batches of M. lysodeikticus ; and the 

 activating effect of biotin was no longer shown by subcultures of the 

 original batch, while it was still reproducible with old samples. Mean- 

 while, a failure to activate lysozyme action with biotin was reported 

 (9). It seems probable that we were dealing with a nonpermanent 

 mutant in some of the colonies, which was the cause of an observed 

 autolysis in the affected strain. [Autolytic or "suicide" colonies have 

 been described as a variant of a Micrococcus tetragenus by Reimann 

 (38)]. It is hoped that an explanation for the activation will be found 

 in the near future. 



The similarity between lysozyme and avidin seems so striking 

 that a relationship between the two deserves further investigation. 

 The formation of avidin, for example, by partial oxidation of lysozyme 

 is being investigated at present. 



Other Mucolytic Enzymes 



Many bacteriolytic agents have been encountered in animal 

 organs and in microorganisms, some of which may be classified as 

 lysozyme-like enzymes. With increasing knowledge of the muco- 

 polysaccharides, knowledge of specific mucolytic enzymes will un- 

 doubtedly increase as well. 



Two enzymes have been encountered which may belong in 

 this group. One is an enzyme — thus far found in human saliva, sub- 

 maxillary glands of animals, and pneumococci — which hydrolyzes 

 one of the two mucopolysaccharides derived from the submaxillary 

 gland. The enzyme is identical neither with hyaluronidase nor with 

 amylase or lysozyme. A search for it in pathogens of the respiratory 

 tract might give some useful information about natural resistance to 

 respiratory infections. The substrate of this enzyme occurs in the 

 glandular extracts as a mucoprotein, composed of about equal parts 

 of a peptide chain and of an acid polysaccharide. The latter contains 

 acetylglucosamine and gluconic acid in equimolar portions (23). 



Another mucolytic enzyme group, on which little work has 



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