xdh-1
C. elegans
xanthine dehydrogenase
What the model saw
Gene: xdh-1 Organism: Caenorhabditis elegans Known functions: xanthine dehydrogenase. 2 iron, 2 sulfur cluster binding. FAD binding. flavin adenine dinucleotide binding. iron ion binding. iron-sulfur cluster binding. metal ion binding. oxidoreductase activity. xanthine dehydrogenase activity.
View unredacted entry
xanthine dehydrogenase. 2 iron, 2 sulfur cluster binding. FAD binding. flavin adenine dinucleotide binding. iron ion binding. iron-sulfur cluster binding. metal ion binding. oxidoreductase activity. xanthine dehydrogenase activity.
Solver output
Xanthine dehydrogenase (XDH-1) catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid, using NAD+ as the electron acceptor under normal conditions but capable of switching to an oxidase form (XO) that transfers electrons to molecular oxygen, generating superoxide and hydrogen oxide. This ROS production is a well-established source of oxidative stress that damages macromolecules and impairs mitochondrial function. In C. elegans, elevated oxidative stress from purine catabolism via xanthine oxidoreductase activity shortens lifespan, as the worm's antioxidant defenses are overwhelmed. The Fe-S cluster and FAD cofactors are central to electron transfer steps that can leak electrons to oxygen, making xdh-1 a net pro-oxidant enzyme. Loss-of-function of xanthine oxidoreductase in model organisms is generally associated with reduced ROS and extended lifespan, placing the normal function of xdh-1 in the anti-longevity category.
GenAge curators classify each gene's normal function as promoting (Pro-Longevity) or opposing (Anti-Longevity) longevity, based on synthesis across studies. Loss-of-function effects can vary from this depending on the manipulation.
Advisor judgment
The model correctly predicted anti_longevity for xdh-1. The mechanistic reasoning is sound: xanthine dehydrogenase/oxidase generates ROS (superoxide/H2O2) during purine catabolism, contributing to oxidative stress that shortens lifespan. Loss-of-function would reduce ROS and extend lifespan, making the normal gene function anti-longevity. The model correctly identifies the Fe-S cluster and FAD cofactors as central to electron transfer. The mechanism class "mitochondrial_dysfunction" is slightly off — the primary mechanism is ROS generation from purine catabolism rather than mitochondrial dysfunction per se — but the overall mechanistic narrative is correct. Confidence of 0.68 is reasonable.
Raw API responses
solver
{
"reasoning": "Xanthine dehydrogenase (XDH-1) catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid, using NAD+ as the electron acceptor under normal conditions but capable of switching to an oxidase form (XO) that transfers electrons to molecular oxygen, generating superoxide and hydrogen oxide. This ROS production is a well-established source of oxidative stress that damages macromolecules and impairs mitochondrial function. In C. elegans, elevated oxidative stress from purine catabolism via xanthine oxidoreductase activity shortens lifespan, as the worm's antioxidant defenses are overwhelmed. The Fe-S cluster and FAD cofactors are central to electron transfer steps that can leak electrons to oxygen, making xdh-1 a net pro-oxidant enzyme. Loss-of-function of xanthine oxidoreductase in model organisms is generally associated with reduced ROS and extended lifespan, placing the normal function of xdh-1 in the anti-longevity category.",
"confidence": 0.68,
"key_pathways": [
"purine catabolism / xanthine oxidoreductase pathway",
"reactive oxygen species (ROS) generation",
"oxidative stress response"
],
"mechanism_class": "mitochondrial_dysfunction",
"longevity_influence": "anti_longevity"
}advisor
{
"notes": "The model correctly predicted anti_longevity for xdh-1. The mechanistic reasoning is sound: xanthine dehydrogenase/oxidase generates ROS (superoxide/H2O2) during purine catabolism, contributing to oxidative stress that shortens lifespan. Loss-of-function would reduce ROS and extend lifespan, making the normal gene function anti-longevity. The model correctly identifies the Fe-S cluster and FAD cofactors as central to electron transfer. The mechanism class \"mitochondrial_dysfunction\" is slightly off — the primary mechanism is ROS generation from purine catabolism rather than mitochondrial dysfunction per se — but the overall mechanistic narrative is correct. Confidence of 0.68 is reasonable.",
"failure_mode": "correct",
"answer_correct": true,
"mechanism_correct": true,
"reasoning_quality": 4,
"ground_truth_questionable": false
}