Serine palmitoyltransferase, long chain base subunit 1, also known as SPTLC1, is a protein which in humans is encoded by the SPTLC1 gene. Serine palmitoyltransferase, which consists of two different subunits, is the key enzyme in sphingolipid biosynthesis. It converts L-serine and palmitoyl-CoA to 3-oxosphinganine with pyridoxal 5'-phosphate as a cofactor. The product of this gene is the long chain base subunit 1 of serine palmitoyltransferase. Mutations in this gene were identified in patients with hereditary sensory neuropathy type 1. Alternatively spliced variants encoding different isoforms have been identified. [provided by RefSeq].
Serine palmitoyltransferase (SPT). The heterodimer formed with LCB2 (SPTLC2 or SPTLC3) constitutes the catalytic core. The composition of the serine palmitoyltransferase (SPT) complex determines the substrate preference. The SPTLC1-SPTLC2-SSSPTA complex shows a strong preference for C16-CoA substrate, while the SPTLC1-SPTLC3-SSSPTA isozyme uses both C14-CoA and C16-CoA as substrates, with a slight preference for C14-CoA. The SPTLC1-SPTLC2-SSSPTB complex shows a strong preference for C18-CoA substrate, while the SPTLC1-SPTLC3-SSSPTB isozyme displays an ability to use a broader range of acyl-CoAs, without apparent preference.