Heptose

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A heptose is a monosaccharide with seven carbon atoms.

They have either an aldehyde functional group in position 1 (aldoheptoses) or a ketone functional group in position 2, 3 or 4 (ketoheptoses). Ketoheptoses have 4 chiral centers, whereas aldoheptoses have 5.

Examples

There are few examples of seven-carbon sugars in nature, among which are:

Related Research Articles

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Monosaccharides, also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built.

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<span class="mw-page-title-main">Ketose</span> Class of carbohydrates

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<span class="mw-page-title-main">Sedoheptulose</span> Chemical compound

Sedoheptulose or pseudoheptulose or D-altro-heptulose is a ketoheptose—a monosaccharide with seven carbon atoms and a ketone functional group. It is one of the few heptoses found in nature, and is found in various fruits and vegetables ranging from carrots and leeks to figs, mangos and avocados.

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<span class="mw-page-title-main">Transketolase</span> Enzyme involved in metabolic pathways

Transketolase is an enzyme that is encoded by the TKT gene. It participates in both the pentose phosphate pathway in all organisms and the Calvin cycle of photosynthesis. Transketolase catalyzes two important reactions, which operate in opposite directions in these two pathways. In the first reaction of the non-oxidative pentose phosphate pathway, the cofactor thiamine diphosphate accepts a 2-carbon fragment from a 5-carbon ketose (D-xylulose-5-P), then transfers this fragment to a 5-carbon aldose (D-ribose-5-P) to form a 7-carbon ketose (sedoheptulose-7-P). The abstraction of two carbons from D-xylulose-5-P yields the 3-carbon aldose glyceraldehyde-3-P. In the Calvin cycle, transketolase catalyzes the reverse reaction, the conversion of sedoheptulose-7-P and glyceraldehyde-3-P to pentoses, the aldose D-ribose-5-P and the ketose D-xylulose-5-P.

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<span class="mw-page-title-main">Transaldolase</span> Enzyme family

Transaldolase is an enzyme of the non-oxidative phase of the pentose phosphate pathway. In humans, transaldolase is encoded by the TALDO1 gene.

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The aminocyclitols are compounds related to cyclitols. They possess features of relative and absolute configuration that are characteristic of their class and have been extensively studied; but these features are not clearly displayed by general methods of stereochemical nomenclature, so that special methods of specifying their configuration are justified and have long been used. In other than stereochemical respects, their nomenclature should follow the general rules of organic chemistry.

Core oligosaccharide is a short chain of sugar residues within Gram-negative lipopolysaccharide (LPS). Core-OS are highly diverse among bacterial species and even within strains of species

<span class="mw-page-title-main">Mannoheptulose</span> Chemical compound

Mannoheptulose is a heptose, a monosaccharide with seven carbon atoms, and a ketose, with the characteristic carbonyl group of the carbohydrate present on a secondary carbon. The sugar alcohol form of mannoheptulose is known as perseitol.

D-glycero-beta-D-manno-heptose-7-phosphate kinase is an enzyme with systematic name ATP:D-glycero-beta-D-manno-heptose 7-phosphate 1-phosphotransferase. This enzyme catalyses the following chemical reaction

D-glycero-beta-D-manno-heptose 1-phosphate adenylyltransferase is an enzyme with systematic name ATP:D-glycero-beta-D-manno-heptose 1-phosphate adenylyltransferase. This enzyme catalyses the following chemical reaction

D-sedoheptulose 7-phosphate isomerase is an enzyme with systematic name D-glycero-D-manno-heptose 7-phosphate aldose-ketose-isomerase. This enzyme catalyses the following chemical reaction

References

  1. Horecker, B. L; Smyrniotis, P. Z (1953). "Transaldolase: The Formation of Fructose-6-Phosphate from Sedoheptulose-7-Phosphate". Journal of the American Chemical Society. 75 (8): 2021. doi:10.1021/ja01104a532.
  2. Patra, Krushna C; Hay, Nissim (2014). "The pentose phosphate pathway and cancer". Trends in Biochemical Sciences. 39 (8): 347. doi:10.1016/j.tibs.2014.06.005. PMC   4329227 . PMID   25037503.
  3. Liu, Xuan; Sievert, James; Arpaia, Mary Lu; Madore, Monica A. (2002-01-01). "Postulated Physiological Roles of the Seven-carbon Sugars, Mannoheptulose, and Perseitol in Avocado". Journal of the American Society for Horticultural Science. 127 (1): 108–114. doi: 10.21273/JASHS.127.1.108 . Retrieved 2018-06-26.
  4. Patricia L. Taylor, Kim M. Blakely, Gladys P. de Leon, John R. Walker, Fiona McArthur, Elena Evdokimova, Kun Zhang, Miguel A. Valvano, Gerard D. Wright, Murray S. Junop (1 February 2008). "Structure and Function of Sedoheptulose-7-phosphate Isomerase, a Critical Enzyme for Lipopolysaccharide Biosynthesis and a Target for Antibiotic Adjuvants". Journal of Biological Chemistry. 283 (5): 2835–2845. doi: 10.1074/jbc.M706163200 . PMID   18056714.{{cite journal}}: CS1 maint: multiple names: authors list (link)