The inhibition of streptococci by lactoperoxidase, thiocyanate and hydrogen peroxide. The oxidation of thiocyanate and the nature of the inhibitory compound.

摘要: Abstract 1. The products of the lactoperoxidase-catalysed oxidation thiocyanate by hydrogen peroxide were sulphate, carbon dioxide and ammonia. Cyanate, sulphite a compound showing increased extinction at 235mμ (the `235 compound') intermediate products. 2. Two intermediates acted as electron acceptors in NADH2. Thus NADH2 was oxidized presence lactoperoxidase (EC 1.11.1.7) Mn2+ compound' an enzyme, NADH2-oxidizing present extracts lactoperoxidase-resistant streptococci. Sulphur dicyanide also acceptor latter reaction. 235compound'wasalsoreducednon−enzymicallybysϕ––te.3.Theglycolysisoflac⊤er⊗sesensitivestrep→coisuspended∈glucosesolutionwas¬∈hibitedbysϕ––te,cyanate,cyanorthe235compound′wasalsoreducednon-enzymicallybysϕte.3.Theglycolysisoflac⊤er⊗sesensitivestrep→coisuspended∈glucosesolutionwas¬∈hibitedbysϕte,cyanate,cyanorthe235 but inhibited sulphur dicyanide. inhibition 0·1mm-sulphur could be reversed, that caused lactoperoxidase, peroxide, washing cells or addition cell-free extract streptococcus. 4. effects on catabolic enzymes resting streptococci very similar to those lactoperoxidase–thiocyanate–hydrogen system. hexokinase completedly inhibited, glucose 6-phosphate dehydrogenase aldolase partially phosphohexokinase little affected both cases.