五炭糖、ペントース

WordNet

any monosaccharide sugar containing five atoms of carbon per molecule

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/02/22 17:54:27」(JST)

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A pentose is a monosaccharide with five carbon atoms.^[1] Pentoses are organized into two groups. Aldopentoses have an aldehyde functional group at position 1. Ketopentoses have a ketone functional group in position 2 or 3.

Aldopentoses

The aldopentoses have three chiral centers and therefore eight different stereoisomers are possible.

D-Arabinose	D-Lyxose	D-Ribose	D-Xylose
L-Arabinose	L-Lyxose	L-Ribose	L-Xylose

Ketopentoses

The 2-ketopentoses have two chiral centers, and therefore four different stereoisomers are possible. The 3-ketopentoses are rare.

D-Ribulose	D-Xylulose
L-Ribulose	L-Xylulose

Properties

The aldehyde and ketone functional groups in these carbohydrates react with neighbouring hydroxyl functional groups to form intramolecular hemiacetals and hemiketals, respectively. The resulting ring structure is related to furan, and is termed a furanose. The ring spontaneously opens and closes, allowing rotation to occur about the bond between the carbonyl group and the neighbouring carbon atom — yielding two distinct configurations (α and β). This process is termed mutarotation.

Ribose is a constituent of RNA, and the related deoxyribose of DNA.

A polymer composed of pentose sugars is called a pentosan.

Tollens’ test for pentoses

The Tollens’ test for pentoses relies on reaction of the furfural with phloroglucinol to produce a colored compound with high molar absorptivity.^[2]

References

^ Pentose, Merriam-Webster
^ Oshitna, K., and Tollens, B., Ueber Spectral-reactionen des Methylfurfurols. Ber. Dtsch. Chem. Ges. 34, 1425 (1901)

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English Journal

Disruption of PHO13 improves ethanol production via the xylose isomerase pathway.

Bamba T1, Hasunuma T2, Kondo A3,4.
AMB Express.AMB Express.2016 Dec;6(1):4. doi: 10.1186/s13568-015-0175-7. Epub 2016 Jan 14.
Xylose is the second most abundant sugar in lignocellulosic materials and can be converted to ethanol by recombinant Saccharomyces cerevisiae yeast strains expressing heterologous genes involved in xylose assimilation pathways. Recent research demonstrated that disruption of the alkaline phosphatase
PMID 26769491

Mechanical insights of oxythiamine compound as potent inhibitor for human transketolase-like protein 1 (TKTL1 protein).

Mariadasse R1, Biswal J1, Jayaprakash P1, Rao GR1, Choubey SK1, Rajendran S1, Jeyakanthan J1.
Journal of receptor and signal transduction research.J Recept Signal Transduct Res.2016 Jun;36(3):233-42. doi: 10.3109/10799893.2015.1080272. Epub 2015 Oct 19.
Transketolase is a connecting link between glycolytic and pentose phosphate pathway, which is considered as the rate-limiting step due to synthesis of large number of ATP molecule and it can be proposed as a plausible target facilitating the growth of cancerous cells suggesting its potential role in
PMID 26481897

Effects of Silicate, Phosphate, and Calcium on the Stability of Aldopentoses.

Nitta S1, Furukawa Y2, Kakegawa T1.
Origins of life and evolution of the biosphere : the journal of the International Society for the Study of the Origin of Life.Orig Life Evol Biosph.2016 Jun;46(2-3):189-202. doi: 10.1007/s11084-015-9472-z. Epub 2015 Nov 11.
Ribose is an important constituent of RNA: ribose connects RNA bases and forms a strand of sugar phosphates. Accumulation of ribose on prebiotic Earth was difficult because of its low stability. Improvement in the yield of ribose by the introduction of borate or silicate in a formose-like reaction h
PMID 26559965

Japanese Journal

Characterization of the chemical diversity of glycosylated mycosporine-like amino acids in the terrestrial cyanobacterium Nostoc commune

Nazifi Ehsan,Wada Naoki,Asano Tomoya,Nishiuchi Takumi,Iwamuro Yoshiaki,Chinaka Satoshi,Matsugo Seiichi,Sakamoto Toshio
Journal of Photochemistry and Photobiology B: Biology 142, 154-168, 2015-01
… The extract contained the following compounds: 7-O-(β-arabinopyranosyl)-porphyra-334 (478 Da), pentose-bound shinorine (464 Da), hexose-bound porphyra-334 (508 Da) and porphyra-334 (346 Da). …
NAID 120005537890

Importance of glucose-6-phosphate dehydrogenase (G6PDH) for vanillin tolerance in Saccharomyces cerevisiae(MICROBIAL PHYSIOLOGY AND BIOTECHNOLOGY)

TrinhThiMyNguyen,Kitajima Sakihito,Izawa Shingo
Journal of bioscience and bioengineering 118(3), 263-269, 2014-09
… Therefore, the pentose phosphate pathway (PPP), through which most NADPH is generated, plays a role in tolerance to furfural. …
NAID 110009857355