Hyaluronidase microbial

Type 3. Microbial hyaluronidases (e.g. Streptococcus hyaluronidase). Microbial hyaluronidases hydrolyse p-N-acetylaminoglycoside bonds of a substrate and simultaneously dehydrate the residue of uronic acid at the non-reducing terminus of the molecule. Substrate specificity of bacterial hyaluronate lyases varies considerably in the different species of microbe producers. Hyaluronidase of Streptococcus pneumoniae has the highest substrate specificity it hydrolyses HA alone and does not destroy other glucosami-noglycans [43]. The hyaluronate lyase, when isolated from Streptococcus pneumoniae, reaches optimal activity at pH 6.0 with the Michaelis constant with respect to HA being equal to 3.8x 10" mol/l (in terms of Michaelis-Menten kinetics) [44]. The presence of Cd3 (about 10 mM) is necessary in order to show the maximum enzyme activity. 

The second type of material includes spores, which may or may not produce disease symptoms but which can germinate in the insect gut and give rise to vegetative bacterial cells which in turn may produce, and exoenzymes such as phospholipases (lecithinases) or hyaluronidase. The phospholipases may produce direct toxic symptoms owing to their action on nervous or other phospholipid-containing tissue. Hyaluronidase breaks down hyaluronic acid and produces effects on animal tissue which are morphologically similar to the breakdown of insect gut wall in the presence of microbial insecticide preparations. 

The partially-purified extract oxidised a range of phenolic substrates, and also contained proteinases and amino acid decarboxylases. Preincubation of a toluene-treated soil enzyme preparation for 12h at 37°C did not affect diphenol oxidase activities, ie. the oxidases appeared to be resistant to attack by the coextracted soil proteinases. Addition of hyaluronidase before preincubation also was without effect. Preincubation with the microbial proteinase, Pronase for I8h at 37°C decreased diphenol oxidase activities by 307o, and by 100% when both Pronase and hyaluronidase were added. The results suggested that the polysaccharides associated with the extracted soil oxidases protected the enzymes from proteolysis and may play a role in stabilizing exocellular enzymes in soils. 

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