Serine palmitoyltransferase small subunit B (Protein ADMP) (Small subunit of serine palmitoyltransferase B) (ssSPTb)
1_MDLRR 6_ VKEYF 11_ SWLYY 16_ QYQII 21_ SCCAV 26_ LEPWE 31_ RSMFN 36_ TILLT 41_ IIAMV 46_ VYTAY 51_ VFIPI 56_ HIRLA 61_ WEFFS 66_ KICGY 71_HSTIS
1: Component of the serine palmitoyltransferase multisubunit enzyme (SPT) that catalyzes the initial and rate-limiting step in sphingolipid biosynthesis by condensing L-serine and activated acyl-CoA (most commonly palmitoyl-CoA) to form long-chain bases (PubMed:19416851). The SPT complex is composed of SPTLC1, SPTLC2 or SPTLC3 and SPTSSA or SPTSSB. Within this complex, the heterodimer consisting of SPTLC1 and SPTLC2/SPTLC3 forms the catalytic core (PubMed:19416851). Within the SPT complex, SPTSSB stimulates the catalytic activity and plays a role in substrate specificity. SPT complexes with this subunit showing a preference for longer acyl-CoAs. The SPTLC1-SPTLC2-SPTSSB complex shows a strong preference for C18-CoA substrate, while the SPTLC1-SPTLC3-SPTSSB isozyme displays an ability to use a broader range of acyl-CoAs, without apparent preference (PubMed:19416851)