argininedependent

Arginedependent is a term used in biology to describe cells or organisms that require arginine from the external environment for growth or survival because they cannot synthesize sufficient arginine endogenously. This dependence can arise from genetic defects in the arginine biosynthesis pathway, regulatory changes that limit synthesis, or adaptations that favor uptake over synthesis.

In mammals and human disease, arginedependent cells often harbor deficiencies in enzymes that produce arginine internally, such as argininosuccinate synthetase (ASS1) or other components of the urea cycle. As a result, these cells rely on extracellular arginine and may be vulnerable to strategies that deplete ambient arginine. This concept is exploited in cancer therapy, where arginine-deprivation approaches aim to selectively target tumor cells with compromised arginine synthesis while sparing normal cells that retain full synthetic capacity. Therapies may involve enzymes that degrade arginine or pathways that limit its availability.

In microbiology, arginedependence can describe strains that are auxotrophic for arginine, meaning they cannot synthesize arginine and must acquire it from their surroundings. Such dependence can influence microbial ecology, growth requirements, and responses to environmental changes.

Detection and study of arginedependent states typically involve growth assays in arginine-free versus arginine-supplemented media, analysis of the expression or activity of arginine biosynthetic enzymes, and metabolic flux measurements. Understanding arginedependent phenotypes informs both basic biology and therapeutic development.