Cbs
D. melanogaster
Cystathionine beta-synthase
What the model saw
Gene: Cbs Organism: Drosophila melanogaster Known functions: Cystathionine beta-synthase. cystathionine beta-synthase. cystathionine beta-synthase activity. nitrite reductase (NO-forming) activity. pyridoxal phosphate binding.
View unredacted entry
Cystathionine beta-synthase. cystathionine beta-synthase. cystathionine beta-synthase activity. nitrite reductase (NO-forming) activity. pyridoxal phosphate binding.
Solver output
Cystathionine beta-synthase (CBS) catalyzes the first committed step of the transsulfuration pathway, converting homocysteine and serine to cystathionine using pyridoxal phosphate as a cofactor. This pathway is a major source of cysteine, which is the rate-limiting precursor for glutathione biosynthesis — the cell's primary antioxidant buffer. By promoting glutathione production, CBS activity reduces oxidative stress, a key driver of aging. Additionally, CBS possesses nitrite reductase (NO-forming) activity, generating nitric oxide (NO), which has well-established cytoprotective, vasodilatory, and signaling roles that support healthspan. Furthermore, CBS activity lowers homocysteine levels; elevated homocysteine is associated with cellular damage, mitochondrial dysfunction, and accelerated aging. Together, these functions — antioxidant defense via the transsulfuration/glutathione axis and NO signaling — strongly support a pro-longevity role.
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 pro_longevity for Cbs in Drosophila melanogaster with a reasonable confidence of 0.72. The mechanistic reasoning is thorough and well-grounded: it correctly identifies the transsulfuration pathway, glutathione biosynthesis as an antioxidant defense mechanism, NO signaling via the nitrite reductase activity (which was explicitly listed in the gene's known functions), and homocysteine-lowering effects. All three pathways cited are biologically plausible and consistent with the known functions provided. The reasoning quality is excellent.
Raw API responses
solver
{
"reasoning": "Cystathionine beta-synthase (CBS) catalyzes the first committed step of the transsulfuration pathway, converting homocysteine and serine to cystathionine using pyridoxal phosphate as a cofactor. This pathway is a major source of cysteine, which is the rate-limiting precursor for glutathione biosynthesis — the cell's primary antioxidant buffer. By promoting glutathione production, CBS activity reduces oxidative stress, a key driver of aging. Additionally, CBS possesses nitrite reductase (NO-forming) activity, generating nitric oxide (NO), which has well-established cytoprotective, vasodilatory, and signaling roles that support healthspan. Furthermore, CBS activity lowers homocysteine levels; elevated homocysteine is associated with cellular damage, mitochondrial dysfunction, and accelerated aging. Together, these functions — antioxidant defense via the transsulfuration/glutathione axis and NO signaling — strongly support a pro-longevity role.",
"confidence": 0.72,
"key_pathways": [
"transsulfuration pathway / glutathione biosynthesis",
"nitric oxide (NO) signaling",
"homocysteine metabolism"
],
"mechanism_class": "other",
"longevity_influence": "pro_longevity"
}advisor
{
"notes": "The model correctly predicted pro_longevity for Cbs in Drosophila melanogaster with a reasonable confidence of 0.72. The mechanistic reasoning is thorough and well-grounded: it correctly identifies the transsulfuration pathway, glutathione biosynthesis as an antioxidant defense mechanism, NO signaling via the nitrite reductase activity (which was explicitly listed in the gene's known functions), and homocysteine-lowering effects. All three pathways cited are biologically plausible and consistent with the known functions provided. The reasoning quality is excellent.",
"failure_mode": "correct",
"answer_correct": true,
"mechanism_correct": true,
"reasoning_quality": 5,
"ground_truth_questionable": false
}