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Acyl-protein Thioesterase
Acyl-protein thioesterases are enzymes that cleave off Lipid-anchored protein, lipid Post-translational modification, modifications on proteins, located on the sulfur atom of cysteine residues linked via a thioester bond. Acyl-protein thioesterases are part of the Alpha/beta hydrolase superfamily, α/β hydrolase superfamily of proteins and have a conserved catalytic triad. For that reason, acyl-protein thioesterases are also able to Hydrolysis, hydrolyze oxygen-linked Ester, ester bonds. Function Acyl-protein thioesterases are involved in the Palmitoylation, depalmitoylation of proteins, meaning they cleave off Palmitoylation, palmitoyl modifications on proteins' cysteine residues. Biological target, Cellular targets include G alpha subunit, trimeric G-alpha proteins, ion channels and Gap-43 protein, GAP-43. Moreover, LYPLA1, human acyl-protein thioesterases 1 and LYPLA2, 2 have been identified as major components in controlling the palmitoylation cycle of the oncogene Ras subfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PPT1
Palmitoyl-protein thioesterase 1 (PPT-1), also known as palmitoyl-protein hydrolase 1, is an enzyme that in humans is encoded by the PPT1 gene. Function PPT-1 a member of the palmitoyl protein thioesterase family. PPT-1 is a small glycoprotein involved in the catabolism of lipid-modified proteins during lysosomal degradation. This enzyme removes thioester In organic chemistry, thioesters are organosulfur compounds with the molecular structure . They are analogous to carboxylate esters () with the sulfur in the thioester replacing oxygen in the carboxylate ester, as implied by the thio- prefix ...-linked fatty acyl groups such as palmitate from cysteine residues. Clinical significance Defects in this gene are a cause of neuronal ceroid lipofuscinosis type 1 (CLN1). Genetic basis and phenotypic correlations of the neuronal ceroid lipofusinoses. eview Warrier V; Vieira M; Mole SE. Biochimica et Biophysica Acta. 1832(11):1827-30, 2013 References Further readin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Homology
Sequence homology is the homology (biology), biological homology between DNA sequence, DNA, RNA sequence, RNA, or Protein primary structure, protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speciation event (orthologs), or a Gene duplication, duplication event (paralogs), or else a Horizontal gene transfer, horizontal (or lateral) gene transfer event (xenologs). Homology among DNA, RNA, or proteins is typically inferred from their nucleotide or amino acid sequence similarity. Significant similarity is strong evidence that two sequences are related by evolutionary changes from a common ancestral sequence. Sequence alignment, Alignments of multiple sequences are used to indicate which regions of each sequence are homologous. Identity, similarity, and conservation The term "percent homology" is often used to mean "sequence similarity”, that is the percen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Membrane
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of a cell, being selectively permeable to ions and organic mole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golgi Apparatus
The Golgi apparatus (), also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic Cell (biology), cells. Part of the endomembrane system in the cytoplasm, it protein targeting, packages proteins into membrane-bound Vesicle (biology and chemistry), vesicles inside the cell before the vesicles are sent to their destination. It resides at the intersection of the secretory, lysosomal, and Endocytosis, endocytic pathways. It is of particular importance in processing proteins for secretion, containing a set of glycosylation enzymes that attach various sugar monomers to proteins as the proteins move through the apparatus. The Golgi apparatus was identified in 1898 by the Italian biologist and pathologist Camillo Golgi. The organelle was later named after him in the 1910s. Discovery Because of its large size and distinctive structure, the Golgi apparatus was one of the first organelles to be discovered and observed in detail. It was d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endomembrane System
The endomembrane system is composed of the different membranes (endomembranes) that are suspended in the cytoplasm within a eukaryotic cell. These membranes divide the cell into functional and structural compartments, or organelles. In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, endosomes, and plasma (cell) membrane among others. The system is defined more accurately as the set of membranes that forms a single functional and developmental unit, either being connected directly, or exchanging material through vesicle transport. Importantly, the endomembrane system does not include the membranes of plastids or mitochondria, but might have evolved partially from the actions of the latter (see below). The nuclear membrane contains a lipid bilayer that encompasses the contents of the nucleus. The endoplasmic reticulum (ER) is a synthesis and transport organelle that branches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
