Pectic acid/pectin

Pectic acid, pectin D-GalA L-Rha L-Ara D-Gal a-(l— 4)-linked D-GalpA (or methyl esterified GalpA) residues containing (1— 2)-linked B-L-Rha/> short arabinan and galactan side chains linked to C-4 of Rhap... 

Pectin analysis also needs more refining and emphasis. Pectic substances are a group of related substances (protopectin, pectin, and pectic acids), each with specific chemical characteristics (9). Both the protopectin and the pectic acid, pectinic acid, form insoluble complexes with metals, especially calcium. These too, like the protein, are concentrated in the persistent middle lamella-primary wall complex. 

The major sources of pectin are plant cell walls. These include sunflower, orange, lemon, carrot, mango, guava, and papaya. Pectin is the methoxyester of pectic acid. Pectin exhibits stability in acidic media. 

PEC-1000 Pechmann reaction Peclet numbers PE coatings Pectic acid Pectic acids [9046-40-6] Pectic materials Pectic substances Pectin... 

Pectins are generally classed according to their ester content as high methoxyl pectins (>50% of the carboxyl groups esterified) or low methoxyl pectins (<50% of carboxyl groups esterified) (pectic acid, methyl ester [9049-34-1]). Low methoxyl pectins, like algins, require calcium for gelation. 

Pekannuss, /. pecan nut, pecan, pektin-artig, a. pectin-like, -ig, a. pectinous. Pektin-korper, m. pectic substance, -s ure, /. pectic acid, -stoff, m., -substanz, /. pectio substance, -zucker, m. arabinose. pelagisch, a. pelagic. 

Schneider and Ziervogel (Ref 2) obtained nitric esters of pectin as intermediate products which were then esterified by means of acet anhydr to the corresponding acetates. In 1949, Rogovin, Treyvas and Shorygina (Ref 5) prepd pectin nitric esters by nitrating pectic acid for 4 hrs at 20° in a mixt composed of 48% HN03,... 

Pectin is a long chain of pectic acid and pectinic acid molecules. Because these acids are sugars, pectin is categorized as a polysaccharide. It is prepared from citrus peels and the remains of apples after they are squeezed for juice. In the plant, pectin is the material that joins the plant cells together. When fungus enzymes break down the pectin in fruit, the fruit gets soft and mushy. 

PDMS. See polydimethylsiloxane pectic acid, 142 pectin, 141-142 pectinic acid, 142... 

Pectin belongs to a family of plant polysaccharides in which the polymer backbone consists of (1— 4)-linked a-D-galacturonic acid repeating-units. Often, (1— 2)-linked a-L-rhamnose residues interrupt the regular polygalacturonate sequence. The high viscosity and gelling properties of pectins are exploited by the food and pharmaceutical industries. X-Ray studies on sodium pectate, calcium pectate, pectic acid, and pectinic acid (methyl ester of pectic acid) have disclosed their structural details. 

Paper ionophoresis, sugars, Maurice Stacey s work, 17 Pectic acid, 350, 352,414 Pectin, 348, 350-353 Pectinic acid, 353 Pentulose, synthesis, 281 D-cryt/iro-Pentulose 5-phosphate, 289 Peptidoglycans, 167-168 Per-O-acetylated di-D-fructose dianhydride derivatives... 

The first paper on the bioactive polysaccharides from Glycyrrhiza uralensis roots was published in 1996 by Kiyohara et al. [57]. They isolated a pectic type polymer with anti-complementary and mitogenic activity that was an acidic pectin, possibly containing rhamnogalacturonan type I as part of the total structure. Degradation of the uronic acid part of the molecule decreased both types of bio activities. The neutral oligosaccharide chains were shown to retain some of the activities of the native polymer, but it was suggested that they should be attached to the acidic core to retain maximum activity. 

Key words xylose-rich pectic polysaccharide, pectin, wheat straw, extraction, sugars, lignin, FT-IR, phenolic acids and aldehydes. 

The enzyme had a requirement for calcium. The addition of EDTA to the reaction mixtures, resulted in complete loss of activity, whereas the addition of CaCl2 increased the activity (figure 8). Presumably, sufficient contaminating calcium ions were present in the dialyzed enzyme and substrate mixture to permit the limited activity of the controls, but apparently these were removed by chelation with EDTA. The optimum concentration was in the range of 5 to 15 M, and higher concentration resulted in a decrease in activity. Phoma medicaginis var. pinodella synthesizes a pectin lyase that lacked an absolute requirement for calcium ions but maximum enzyme activity required the presence of 1 mM Ca [25]. The lyase from Fusarium solani f sp. phaseoli, that is active on pectin and pectic acid, is calcium-dependent [30]. Most of the pectate lyases characterized are calcium-dependent the pectate lyase from Rhizoctonia solani [34] and the endopectate lyase fi om Fusarium solani f sp. pisi [31]. 

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