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Ribose 5-phosphate (R5P) is both a product and an intermediate of the pentose phosphate pathway. The last step of the oxidative reactions in the pentose phosphate pathway is the production of ribulose 5-phosphate. Depending on the body's state, ribulose 5-phosphate can reversibly isomerize to ribose 5-phosphate.
D-Ribose pyranase is an enzyme that catalyzes the interconversion of β-D-ribopyranose and β-D-ribofuranose. [1] This enzyme is an isomerase that has only been found in bacteria and viruses . It has two known functions of helping transport ribose into cells and producing β- D -ribofuranose, which can later be used to make ribose 5-phosphate ...
A key regulatory step is the production of 5-phospho-α-D-ribosyl 1-pyrophosphate by ribose-phosphate diphosphokinase, which is activated by inorganic phosphate and inactivated by purine ribonucleotides. It is not the committed step to purine synthesis because PRPP is also used in pyrimidine synthesis and salvage pathways.
Ribose-5-phosphate isomerase (Rpi) encoded by the RPIA gene is an enzyme (EC 5.3.1.6) that catalyzes the conversion between ribose-5-phosphate (R5P) and ribulose-5-phosphate (Ru5P). It is a member of a larger class of isomerases which catalyze the interconversion of chemical isomers (in this case structural isomers of pentose ).
ATP + d-ribose ⇌ ADP + d-ribose 5-phosphate. Thus, the two substrates of this enzyme are ATP and d-ribose, whereas its two products are ADP and d-ribose 5-phosphate. The systematic name of this enzyme class is ATP: d-ribose 5-phosphotransferase. Other names in common use include deoxyribokinase, ribokinase (phosphorylating), and d-ribokinase.
In enzymology, a phosphoribokinase (EC 2.7.1.18) is an enzyme that catalyzes the chemical reaction. ATP + D-ribose 5-phosphate ADP + D-ribose 1,5-bisphosphate. Thus, the two substrates of this enzyme are ATP and D-ribose 5-phosphate, whereas its two products are ADP and D-ribose 1,5-bisphosphate.
Nucleotides are initially made with ribose as the sugar component, which is a feature of RNA. DNA, however, requires deoxyribose, which is missing the 2'-hydroxyl (-OH group) on the ribose. The reaction to remove this -OH is catalyzed by ribonucleotide reductase. This enzyme converts NDPs (nucleoside-diphosphate) to dNDPs (deoxynucleoside ...
The general structure of a ribonucleotide consists of a phosphate group, a ribose sugar group, and a nucleobase, in which the nucleobase can either be adenine, guanine, cytosine, or uracil. Without the phosphate group, the composition of the nucleobase and sugar is known as a nucleoside.