Alpha-enolase

Alpha-enolase (ENO1) is a glycolytic enzyme that catalyzes the reversible conversion of 2-phosphoglycerate to phosphoenolpyruvate (UniProt: P06733). Beyond its core metabolic role, the protein participates in growth control, hypoxia tolerance, and immune regulation. It can function as a plasminogen receptor and activator on neuronal cell surfaces, potentially contributing to the fibrinolytic system, and acts as a transcriptional repressor at the myc promoter.

ENO1 is widely expressed across tissues and has been implicated in various cellular processes including allergic responses and immunoglobulin production (UniProt: P06733). The protein's multifunctional nature—spanning glycolysis, transcriptional regulation, and cell-surface receptor activity—positions it at multiple biological nodes.

In Alzheimer's Disease, ENO1 is upregulated in post-mortem AD brain tissue compared to age-matched controls (mean log2FC: 0.1506) across one subcellular fraction analyzed in TMT-labeled proteomics (Chaparral AD proteomics). This elevation may reflect metabolic stress, neuroinflammatory responses, or altered plasminogen signaling in the AD brain microenvironment, though the modest fold-change warrants further investigation of its functional significance in disease pathology.