| 释义 |
pentose Chem.|ˈpɛntəʊs|
[f. Gr. πέντε five + -ose2; first formed as G. pentose (E. Fischer 1890, in Ber. d. Deut. Chem. Ges. XXIII. 934).]
1. ‘A name given to compounds resembling glucose, but having only five atoms of carbon in the molecule; e.g. tetra-oxy-valeric aldehyde.’ Any of the monosaccharides with the formula C5H10O5, among which are ribose and several other naturally occurring sugars.
1890[see heptose s.v. hepta-]. 1892Morley & Muir Watts' Dict. Chem. III. 807/2. 1899 J. Cagney Jaksch's Clin. Diagn. vii. 327 The quantitative determination of the pentose group of sugars. Ibid. 334 It appears that pentoses are frequently contained in beer. 1916A. P. Mathews Physiol. Chem. ii. 30 The pentoses generally occur in nature in gums and..polysaccharides. 1927Jrnl. Biol. Chem. LXXIII. 18 Any method of pentose estimation..must prove to be efficacious, not only for xylose and arabinose, but especially for d-ribose, for it is as ribose compounds that one finds pentose in the body. 1953Fruton & Simmonds Gen. Biochem. xvii. 381 A number of pentoses have been found in nature; perhaps the most important of these is d-ribose,..a constituent of nucleic acids and of several nucleotides (ATP, DPN, etc.). 1973R. G. Krueger et al. Introd. Microbiol. viii. 263/2 Pentoses (five-carbon sugars) are carbon and energy sources for many microorganisms.
2. Special combs.: pentose nucleic acid, a nucleic acid in which the sugar is a pentose; (effectively synonymous with ribonucleic acid, RNA); pentose phosphate cycle, pathway, or shunt, a cyclic pathway in the body and in higher plants by which glucose phosphate is converted to a pentose phosphate with the reduction of NADP, the pentose phosphate being afterwards converted into phosphates of a hexose and a triose or else incorporated into nucleotides.
1934Biochem. Jrnl. XXVIII. 2108 The pentose nucleic acid of the pancreas gland. 1947Thorpe's Dict. Appl. Chem. (ed. 4) VIII. 622/1 The idea has arisen that deoxypentose nucleic acid is present in the nucleus, pentose nucleic acid in the cytoplasm. 1953Fruton & Simmonds Gen. Biochem. vii. 184 Although it was once thought that the pentose nucleic acids were characteristic of plant tissues whereas the deoxypentose nucleic acids were confined to animal cells, this separation has been shown to be incorrect. 1968I. L. Finar Org. Chem. (ed. 4) II. xvi. 724 The nucleic acids are classified according to the nature of the sugar present: the pentose nucleic acids or ribonucleic acids (R.N.A.), and the deoxypentose nucleic acids or deoxyribonucleic acids (D.N.A.).
1960McGraw-Hill Encycl. Sci. & Technol. II. 40/1 The pentose phosphate pathway of glucose decomposition involves hexose monophosphates and pentose monophosphates. 1963C. H. Doering tr. Karlson's Introd. Mod. Biochem. xv. 269 (heading) Glucose oxidation through the pentose phosphate cycle. 1964W. G. Smith Allergy & Tissue Metabolism viii. 85 Supplies of NADPH2 can be made available by shunting some of the available glucose-6-phosphate into reactions which form ribulose-5-phosphate. This in turn can be converted back to glucose-6-phosphate... The whole process is sometimes referred to as the pentose phosphate shunt. 1970R. W. McGilvery Biochem. xxiii. 568 The adrenal cortex has an active pentose phosphate pathway that can provide NADPH in the cytosol by oxidizing glucose-6-phosphate. |