Category: Xylose
-
The halloween genes
The halloween genes are a set of genes identified in Drosophila melanogaster that influence embryonic development. All of the genes code for cytochrome P450 enzymes in the ecdysteroidogenic pathway (biosynthesis of ecdysone from cholesterol). Ecdysteroids such as 20-hydroxyecdysone and ecdysone influence many of the morphological, physiological, biochemical changes that occur during molting in insects. Steroid hormones control many aspects of reproduction, development, and homeostasis in higher organisms. In arthropods, steroid hormones play equal or even more…
-
Chrysolina beetles, including Chrysolina coerulans, have cardiac glycosides (including xylose) in their defensive glands
The defensive secretions of some chrysomelid beetles belonging to the genera Chrysolina, Chrysochloa, and Dlochrysa contain complex mixtures of cardenolides. The spectral data for some of these compounds suggest that they are monohydroxylated digitoxigenin derivatives linked to a pentose (such as xylose or arabinose). Evidence indicates that the beetles do not sequester these steroid glycosides…
-
Xylose is the first saccharide added to the serine or threonine in the proteoglycan type O-glycosylation
Xylose is the first saccharide added to the serine or threonine in the proteoglycan type O-glycosylation, and, so, it is the first saccharide in biosynthetic pathways of most anionic polysaccharides such as heparan sulfate and chondroitin sulfate. Definitions Proteoglycans are proteins that are heavily glycosylated. The basic proteoglycan unit consists of a “core protein” with one or more covalently attached glycosaminoglycan (GAG) chain(s). The point of attachment is a serine (Ser) residue to which the glycosaminoglycan is joined through…
-
Xylose is the main building block for the hemicellulose
Xylose is the main building block for the hemicellulose xylan, which comprises about 30% of some plants (birch for example), far less in others (spruce and pine have about 9% xylan). Xylose is otherwise pervasive, being found in the embryos of most edible plants. It was first isolated from wood by Finnish scientist, Koch, in 1881, but first became…
-
Reduction of xylose by catalytic hydrogenation produces the sugar substitute xylitol
Xylose (cf. Ancient Greek: ξύλον, xylon, “wood”) is a sugar first isolated from wood, and named for it. Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes an aldehyde functional group. It is derived from hemicellulose, one of the main constituents of biomass. Like most sugars, it can adopt several structures depending on conditions. With its free aldehyde group,…