Fructoselysine-6-kinase (sometimes also called fructoselysine kinase) is a kinase enzyme.
In biochemistry, a kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates. This process is known as phosphorylation, where the substrate gains a phosphate group and the high-energy ATP molecule donates a phosphate group. This transesterification produces a phosphorylated substrate and ADP. Conversely, it is referred to as dephosphorylation when the phosphorylated substrate donates a phosphate group and ADP gains a phosphate group. These two processes, phosphorylation and dephosphorylation, occur four times during glycolysis. Kinases are part of the larger family of phosphotransferases. Kinases should not be confused with phosphorylases, which catalyze the addition of inorganic phosphate groups to an acceptor, nor with phosphatases, which remove phosphate groups. The phosphorylation state of a molecule, whether it be a protein, lipid, or carbohydrate, can affect its activity, reactivity, and its ability to bind other molecules. Therefore, kinases are critical in metabolism, cell signalling, protein regulation, cellular transport, secretory processes, and many other cellular pathways, which makes them very important to human physiology.
Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions. The molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the 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 a new field of pseudoenzyme analysis has recently grown up, recognising 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.
It phosphorylates fructoselysine on the fructose residue's 6-carbon to form fructoselysine-6-phosphate, as the first step to breaking it down to glucose-6-phosphate and lysine for use as a food source. The second step is accomplished by the enzyme fructoselysine-6-phosphate deglycase. [1]
In chemistry, phosphorylation of a molecule is the attachment of a phosphoryl group. Together with its counterpart, dephosphorylation, it is critical for many cellular processes in biology. Phosphorylation is especially important for protein function; for example, this modification activates almost half of the enzymes present in yeast, thereby regulating their function. Many proteins are phosphorylated temporarily, as are many sugars, lipids, and other molecules.
Fructoselysine is an Amadori adduct of glucose to lysine.
Lysine (symbol Lys or K) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain lysyl ((CH2)4NH2), classifying it as a basic, charged (at physiological pH), aliphatic amino acid. It is encoded by the codons, AAA and AAG. Like almost all other amino acids, the α-carbon is chiral and lysine may refer to either enantiomer or a racemic mixture of both. For the purpose of this article, lysine will refer to the biologically active enantiomer L-lysine, where the α-carbon is in the S configuration.
In E. coli , both enzymes are located on the frl (fructoselysine) operon in order to be transcribed simultaneously. In this context it is known as gene 'frlD' and fructoselysine 6-phosphate deglycase as 'frlB'. [2]
In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splicing to create monocistronic mRNAs that are translated separately, i.e. several strands of mRNA that each encode a single gene product. The result of this is that the genes contained in the operon are either expressed together or not at all. Several genes must be co-transcribed to define an operon.
Glycolysis (from glycose, an older term for glucose + -lysis degradation) is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+. The free energy released in this process is used to form the high-energy molecules ATP (adenosine triphosphate) and NADH (reduced nicotinamide adenine dinucleotide). Glycolysis is a sequence of ten enzyme-catalyzed reactions. Most monosaccharides, such as fructose and galactose, can be converted to one of these intermediates. The intermediates may also be directly useful. For example, the intermediate dihydroxyacetone phosphate (DHAP) is a source of the glycerol that combines with fatty acids to form fat.
Phosphofructokinase-1 (PFK-1) is one of the most important regulatory enzymes of glycolysis. It is an allosteric enzyme made of 4 subunits and controlled by many activators and inhibitors. PFK-1 catalyzes the important "committed" step of glycolysis, the conversion of fructose 6-phosphate and ATP to fructose 1,6-bisphosphate and ADP. Glycolysis is the foundation for respiration, both anaerobic and aerobic. Because phosphofructokinase (PFK) catalyzes the ATP-dependent phosphorylation to convert fructose-6-phosphate into fructose 1,6-bisphosphate and ADP, it is one of the key regulatory and rate limiting steps of glycolysis. PFK is able to regulate glycolysis through allosteric inhibition, and in this way, the cell can increase or decrease the rate of glycolysis in response to the cell's energy requirements. For example, a high ratio of ATP to ADP will inhibit PFK and glycolysis. The key difference between the regulation of PFK in eukaryotes and prokaryotes is that in eukaryotes PFK is activated by fructose 2,6-bisphosphate. The purpose of fructose 2,6-bisphosphate is to supersede ATP inhibition, thus allowing eukaryotes to have greater sensitivity to regulation by hormones like glucagon and insulin.
Galactokinase is an enzyme (phosphotransferase) that facilitates the phosphorylation of α-D-galactose to galactose 1-phosphate at the expense of one molecule of ATP. Galactokinase catalyzes the second step of the Leloir pathway, a metabolic pathway found in most organisms for the catabolism of β-D-galactose to glucose 1-phosphate. First isolated from mammalian liver, galactokinase has been studied extensively in yeast, archaea, plants, and humans.
Pyridoxal phosphate (PLP, pyridoxal 5'-phosphate, P5P), the active form of vitamin B6, is a coenzyme in a variety of enzymatic reactions. The Enzyme commission has catalogued more than 140 PLP-dependent activities, corresponding to ~4% of all classified activities. The versatility of PLP arises from its ability to covalently bind the substrate, and then to act as an electrophilic catalyst, thereby stabilizing different types of carbanionic reaction intermediates.
The Entner–Doudoroff pathway describes a pathway—a series of enzyme-catalyzed chemical reactions—that are active in bacterial primary metabolism, a pathway that catabolizes glucose to pyruvic acid using enzymes distinct either from those used in glycolysis or the pentose phosphate pathway. The ED pathway was first reported by Michael Doudoroff and Nathan Entner from the Bacteriology Department at the University of California, Berkeley in 1952. Recent work on the Entner–Duodoroff pathway has shown that its use is not restricted to prokaryotes as was previously thought. Specifically, there is direct evidence that Hordeum vulgare uses the Entner–Doudoroff pathway. Use of the Entner–Duodoroff pathway among other plants such as mosses and ferns is also probably widespread, based on preliminary sequencing data analysis.
Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined together to form macromolecules. This process often consists of metabolic pathways. Some of these biosynthetic pathways are located within a single cellular organelle, while others involve enzymes that are located within multiple cellular organelles. Examples of these biosynthetic pathways include the production of lipid membrane components and nucleotides. Biosynthesis is usually synonymous with anabolism.
Adenylate kinase is a phosphotransferase enzyme that catalyzes the interconversion of adenine nucleotides. By constantly monitoring phosphate nucleotide levels inside the cell, ADK plays an important role in cellular energy homeostasis.
Argininosuccinate synthase or synthetase is an enzyme that catalyzes the synthesis of argininosuccinate from citrulline and aspartate. In humans, argininosuccinate synthase is encoded by the ASS gene located on chromosome 9.
Ribonuclease III (BRENDA 3.1.26.3) is a type of ribonuclease that recognizes dsRNA and cleaves it at specific targeted locations to transform them into mature RNAs. These enzymes are a group of endoribonucleases that are characterized by their ribonuclease domain, which is labelled the RNase III domain. They are ubiquitous compounds in the cell and play a major role in pathways such as RNA precursor synthesis, RNA Silencing, and the pnp autoregulatory mechanism.
Amino acid synthesis is the set of biochemical processes by which the various amino acids are produced from other compounds. The substrates for these processes are various compounds in the organism's diet or growth media. Not all organisms are able to synthesize all amino acids. Humans are an excellent example of this, since humans can only synthesize 11 of the 20 standard amino acids, and in time of accelerated growth, histidine, can be considered an essential amino acid.
6-Phosphogluconolactonase is a cytosolic enzyme found in all organisms that catalyzes the hydrolysis of 6-phosphogluconolactone to 6-phosphogluconic acid in the oxidative phase of the pentose phosphate pathway. The tertiary structure of 6PGL employs an α/β hydrolase fold, with active site residues clustered on the loops of the α-helices. Based on the crystal structure of the enzyme, the mechanism is proposed to be dependent on proton transfer by a histidine residue in the active site. 6PGL selectively catalyzes the hydrolysis of δ-6-phosphogluconolactone, and has no activity on the γ isomer.
Phosphofructokinase is a kinase enzyme that phosphorylates fructose 6-phosphate in glycolysis.
Glucose-1,6-bisphosphate synthase is a type of enzyme called a phosphotransferase and is involved in mammalian starch and sucrose metabolism. It catalyzes the transfer of a phosphate group from 1,3-bisphosphoglycerate to glucose-1-phosphate, yielding 3-phosphoglycerate and glucose-1,6-bisphosphate.
In enzymology, a L-fuculose-phosphate aldolase is an enzyme that catalyzes the chemical reaction
In enzymology, a guanylate kinase is an enzyme that catalyzes the chemical reaction
In enzymology, a [isocitrate dehydrogenase (NADP+)] kinase (EC 2.7.11.5) is an enzyme that catalyzes the chemical reaction:
In enzymology, a nucleoside-phosphate kinase is an enzyme that catalyzes the chemical reaction
Tetraacyldisaccharide 4'-kinase is an enzyme that phosphorylates the 4'-position of a tetraacyldisaccharide 1-phosphate precursor (DS-1-P) of lipopolysaccharide lipid A. This lipid forms outer membranes of Gram-negative bacteria. This enzyme catalyzes the chemical reaction
In molecular biology the fructosamine kinase family is a family of enzymes. This family includes eukaryotic fructosamine-3-kinase enzymes which may initiate a process leading to the deglycation of fructoselysine and of glycated proteins and in the phosphorylation of 1-deoxy-1-morpholinofructose, fructoselysine, fructoseglycine, fructose and glycated lysozyme. The family also includes ketosamine-3-kinases (KT3K). Ketosamines derive from a non-enzymatic reaction between a sugar and a protein. Ketosamine-3-kinases (KT3K) catalyse the phosphorylation of the ketosamine moiety of glycated proteins. The instability of a phosphorylated ketosamine leads to its degradation, and KT3K is thus thought to be involved in protein repair.
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