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Only the L-stereoisomer appears naturally in proteins. It is not essential to the human diet, since it is synthesized in the body from other metabolites, including glycine. Serine was first obtained from silk protein, a particularly rich source, in 1865 by Emil Cramer. [5] Its name is derived from the Latin for silk, sericum. Serine's structure ...
Phosphatidylserine (abbreviated Ptd-L-Ser or PS) is a phospholipid and is a component of the cell membrane. [1] It plays a key role in cell cycle signaling, specifically in relation to apoptosis . It is a key pathway for viruses to enter cells via apoptotic mimicry . [ 2 ]
The synthesis of sphingomyelin involves the enzymatic transfer of a phosphocholine from phosphatidylcholine to a ceramide. The first committed step of sphingomyelin synthesis involves the condensation of L-serine and palmitoyl-CoA. This reaction is catalyzed by serine palmitoyltransferase. The product of this reaction is reduced, yielding ...
In microorganisms and plants, the enzyme serine acetyltransferase catalyzes the transfer of acetyl group from acetyl-CoA onto L-serine to yield O-acetyl-L-serine. [39] The following reaction step, catalyzed by the enzyme O-acetyl serine (thiol) lyase, replaces the acetyl group of O-acetyl-L-serine with sulfide to yield cysteine. [40]
The long-chain bases, sometimes simply known as sphingoid bases, are the first non-transient products of de novo sphingolipid synthesis in both yeast and mammals. These compounds, specifically known as phytosphingosine and dihydrosphingosine (also known as sphinganine, [4] although this term is less common), are mainly C 18 compounds, with somewhat lower levels of C 20 bases. [5]
Serine C-palmitoyltransferase is expressed in a large number of species from bacteria to humans. The bacterial enzyme is a water-soluble homodimer [2] whereas in eukaryotes the enzyme is a heterodimer which is anchored to the endoplasmic reticulum. [3] Humans and other mammals express three paralogous subunits SPTLC1, SPTLC2, and SPTLC3.
Serine dehydratase has also been found to be absent in human colon carcinoma and rat sarcoma. The observed enzyme imbalance in these tumors shows that an increased capacity for the synthesis of serine is coupled to its utilization for nucleotide biosynthesis as a part of the commitment to cellular replication in cancer cells.
The 3 substrates of this enzyme are ATP, L-serine, and tRNA(Ser), whereas its 3 products are AMP, diphosphate, and L-seryl-tRNA(Ser). This enzyme belongs to the family of ligases, to be specific those forming carbon-oxygen bonds in aminoacyl-tRNA and related compounds. The systematic name of this enzyme class is L-serine:tRNASer ligase (AMP ...