Arginine-ornithine antiporter (ArcD) (ArcD)

The Arginine-ornithine antiporter (ArcD) is a specialized membrane transport protein that serves as the gateway for the Arginine Deiminase System (ADS) in commensal oral streptococci, including Streptococcus sanguinis and Streptococcus gordonii (Burne & Marquis, 2000). It facilitates the stoichiometric exchange of extracellular L-arginine for intracellular ornithine, ensuring a continuous supply of substrate for intracellular catabolism (Liu et al., 2012). Within the cell, the ADS converts arginine into ammonia, carbon dioxide, and ATP; the resulting ammonia is critical for neutralizing the lactic acid produced by cariogenic bacteria like Streptococcus mutans (Nascimento et al., 2014). By maintaining a neutral pH environment within the dental plaque, ArcD activity helps prevent the demineralization of tooth enamel and promotes a microbial balance favorable to oral health (Griswold et al., 2004). Consequently, this transport system is a key target for prebiotic interventions, such as arginine-supplemented oral care products, which aim to enhance the alkali-generating capacity of the oral microbiome to combat dental caries (Nascimento et al., 2014).

Other names

Arginine:ornithine exchangerADS-associated arginine transporterArcD proteinArginine-ornithine exchange protein

Facilitates the uptake of arginine into commensal oral streptococci to fuel the arginine deiminase system, resulting in ammonia production and plaque pH neutralization.