Glucose transport in Streptococcus agalactiae and its inhibition by lactoperoxidase-thiocyanate-hydrogen peroxide

Abstract

Transport of 2-deoxyglucose or glucose in Streptococcus agalactiae was strongly inhibited if the cells were first exposed to a combination of lactoperoxidase-thiocyanate-hydrogen peroxide (LP-complex). The inhibition was completely reversible with dithiothreitol. N-ethylmaleimide and p-chloromercuribenzoate inhibited sugar transport, and the inhibition was also reversible with dithiothreitol. Sodium fluoride also inhibited sugar transport. Glucolysis was completely inhibited, and dithiothreitol completely reversed the inhibition. Phosphoenolpyruvate-dependent phosphotransferase activity in S. agalactiae was not strongly inhibited by the LP-complex. Interference of the entry of glucose into cells of S. agalactiae by the LP-complex could well account for its growth inhibitory properties with this organism. The inhibition of glucose transport by the LP-complex and its reversibility with dithiothreitol suggest the modification of functional sulfhydryl groups in the cell membrane as a cause of transport inhibition.

Simple filter paper procedure for estimation of glucose uptake via group translocation by whole-cell suspensions of bacteria

“…Glucose transport by toluene-acetonetreated E. coli and S. mutans. E. coli and S. mutans were treated with toluene-acetone as described in reference 9. In agreement with an earlier report (5), we also found it necessary to freeze-thaw S. mutans before toluene-acetone treatment to obtain a PEP response. Prewarmed permeabilized bacteria were added to a reaction mixture containing (final concentration) 25 mM PB, 1 mM MgCl2, 10 mM NaF, and 1 mM PEP.…”

Hydrogen peroxide excretion by oral streptococci and effect of lactoperoxidase-thiocyanate-hydrogen peroxide

“…Glycolysis has been reported to be blocked at several sites by the products of the lactoperoxidase-thiocyanate-hydrogen peroxide reaction. Transport of glucose can be inhibited (27), as can the activity of hexokinase (2,32) and glyceraldehyde 3-phosphate dehydrogenase (26). This inhibition seems to be due to an oxidation of bacterial sulfhydryl groups to yield sulfenic acid and sulfenyl thiocyanate derivatives (28, 41).…”

Inhibition of Escherichia coli respiratory enzymes by the lactoperoxidase-hydrogen peroxide-thiocyanate antimicrobial system

“…1991). These compounds react with microbial sulfhydryls (Pruitt and Reiter 1985; Reiter and Perraudin 1991) and inhibit various cellular functions, such as glycolysis (Oram and Reiter 1966; Adamson and Pruitt 1981), membrane transport of sugars and amino acids (Hamon and Klebanoff 1973; Mickelson 1977; Loimaranta et al . 1998), and respiration (Thomas and Aune 1978; Law and John 1981).…”