A Comprehensive Monograph on Serine (DB00133): From Core Metabolism to Therapeutic Frontiers

Executive Summary

Serine is a proteinogenic α-amino acid that occupies a position of profound significance in human biochemistry and pharmacology. Traditionally classified as a nutritionally non-essential amino acid due to the body's capacity for endogenous synthesis, a more nuanced understanding now recognizes it as "conditionally essential." This revised status reflects the reality that endogenous production is often insufficient to meet the metabolic demands imposed by various physiological states, such as rapid growth and development, or pathological conditions, including certain genetic and neurodegenerative disorders. With the DrugBank identifier DB00133 and CAS Number 56-45-1, this small molecule is far more than a simple structural component; it is a central hub of intermediary metabolism.

The metabolic indispensability of L-serine, the naturally occurring stereoisomer, stems primarily from its role as the principal donor of one-carbon units to the folate cycle. This function establishes a direct and critical biochemical link between central carbon metabolism (glycolysis) and the de novo synthesis of essential biomolecules, including purines and pyrimidines, the building blocks of DNA and RNA. Consequently, serine metabolism is intrinsically tied to cellular proliferation, growth, and repair. Furthermore, L-serine serves as a key precursor for the synthesis of other amino acids, such as glycine and cysteine, and is a foundational component of critical lipids, including phospholipids and sphingolipids, which are vital for the structural integrity and function of all cell membranes, particularly within the central nervous system (CNS).