Lysozyme 179 



glycogen molecules amylase attacks the molecule at multiple points 

 leading to the formation of dextrins (6-8 glucose units) which are 

 unable to give a blue colour with aqueous iodine, these are split 

 finally to about 87 per cent of maltose and 13 per cent glucose. 

 In the more common branched amylases, the branching occurs 

 through 1 : 6 linkages which are not susceptible to amylase action 

 so that the hydrolytic products also contain iso-maltose (6-gluco- 

 sido glucose) (Myrback and Neumiiller, 1950). Amylase release 

 from salivary gland has been studied in vitro (Hokin and Hokin, 

 1954; Hokin and Sherwin, 1957) and in vivo by Schneyer and 

 Schneyer (1956). Variation in the amylase content of the salivary 

 glands in different genetic mouse strains has been reported 

 (Schneyer, 1958). 



LYSOZYME 



Fleming (1922 ; Fleming and Allison, 1922) found that the saliva, 

 tears, nasal mucus and serum as well as extracts of many tissues 

 were capable of lysing certain bacteria. The substance responsible 

 had enzymatic properties and was named lysozyme. A similar sub- 

 stance is present in egg white and certain plant materials. This 

 substance has been isolated in crystalline form from egg white and 

 spleen (Alderton, Ward and Fevold, 1945; Jolles and Fromageot, 

 1954) as a small protein of molecular weight 14,000 to 15,000 with 

 an alkaline isoelectric point. The two lysozymes differ in amino- 

 acid composition. Cat and human saliva lysozymes which have 

 not so far been obtained pure can be distinguished immunologic- 

 ally (Roberts, Macgraith and Florey, 1938). The term lysozyme, 

 therefore, applies to a family of substances. Lysozyme is bacterio- 

 lytic for organisms belonging to the genera Bacillus, Micrococcus, 

 Staphylococcus, Streptococcus, Proteus and Brucella. Lysis occurs 

 due to hydrolysis of a constituent of the bacterial wall which ap- 

 pears to be a mucoprotein from which the enzyme is able to split 

 off N-acetyl-hexosamine and oligosaccharides containing N-ace- 

 tyl-hexosamine and a keto hexose (Meyer, Palmer, Thompson and 

 Khorazo, 1936; Epstein and Chain, 1940; Salton, 1957). Measure- 

 ment of the lysozyme concentration in saliva is difficult because of 

 the strong tendency of lysozyme to form inactive complexes with 

 acidic polymers such as the sialomucins as well as due to inter- 

 ference by soluble substrates in the saliva. The enzyme is present 

 in both parotid and submaxillary saliva in man and in animals 



