SHMT1s

SHMT1s refer to serine hydroxymethyltransferase 1 (SHMT1) enzymes, which are critical metabolic enzymes involved in one-carbon metabolism. These enzymes play a key role in the synthesis of glycine and the regeneration of tetrahydrofolate (THF), a cofactor essential for nucleotide biosynthesis and methylation reactions. SHMT1 is a cytosolic isoform found in most eukaryotic cells, including humans, where it facilitates the transfer of a hydroxymethyl group from serine to THF, producing glycine and 5,10-methylene-THF.

SHMT1 is encoded by the *SHMT1* gene located on chromosome 17 in humans. The enzyme exists in both monomeric and dimeric forms, with its activity regulated by substrate availability, product inhibition, and allosteric modulation. Mutations in *SHMT1* have been linked to rare metabolic disorders, such as severe combined immunodeficiency (SCID) and developmental delays, highlighting its importance in cellular function.

Beyond its metabolic role, SHMT1 has been implicated in cancer biology. Elevated SHMT1 expression is observed in certain malignancies, where it supports rapid cell proliferation by providing one-carbon units for nucleotide synthesis. This has led to interest in SHMT1 as a potential therapeutic target in oncology, though research remains exploratory.

SHMT1 should not be confused with SHMT2, its mitochondrial counterpart, which operates in a similar pathway but is localized to the mitochondria. While SHMT1 is primarily cytosolic, SHMT2 contributes to mitochondrial one-carbon metabolism, particularly in cells with high energy demands.

In summary, SHMT1 is a fundamental enzyme in cellular metabolism, essential for glycine synthesis and folate recycling. Its dysregulation can impact health, particularly in immune function and cancer progression, making it a subject of ongoing biological and clinical investigation.