Glycoproteins carbohydrate content

The system consists of LP (EC 1.11.1.7) and the substrates thiocyanate and H2O2. The enzyme, a glycoprotein (carbohydrate content 10%), consists of 612 amino acid residues (Mr 78,000, IP 9.6) and Fe-protoporphyrin IX, which as the prosthetic group carries out the catalysis, as described in 2.3.2.2. Thiocyanate takes part in this reaction process as the electron donor AH. Lactoperoxidase is one of the heat stable enzymes of milk, especially when the structure is fixed by Ca ions. It is still active after 30 min at 63 °C (neutral pH) and after 15 s at 72 °C, but it is inactive after only 2.5 s at 80 °C. Acidification (pH 5.3) accelerates the inactivation by liberating the Ca ions. After... 

Glycoproteins occur in most organisms, from bacteria to humans. Many vimses also contain glycoproteins, some of which have been much investigated, in part because they are very suitable for biosynthetic studies. Numerous proteins with diverse functions are glycoproteins (Table 47-1) their carbohydrate content ranges from 1% to over 85% by weight. 

This glycoprotein hormone is a heterodimer, composed of an a and a P subunit and approximately 45 per cent of its molecular mass is carbohydrate. Reported molecular masses range from 52 to 68 kDa, a reflection of the potential variability of the hormone s carbohydrate content. 

Glycoproteins are smaller than proteoglycans, and have far more variability in protein and carbohydrate content between different types. In both types of molecule, the oligosaccharide moieties are covalently attached to the protein via serine, threonine... 

These new estimates of the particle weight change the number of copies of the viral glycoprotein per viral particle. The polypeptides (capsid, 1, E2, and 3) are present in equimolar amounts (Garoff et al., 1974). Since 56.6% of the virus is protein (leaving out the carbohydrate content) the viral particle (using a molecular weight of 41-42 x 10 ) should contain about 180 copies of each protein. 

The Carbohydrate Content of Some Glycopeptides and of the Tamm-Horsfall Glycoprotein Found in Normal Urine... 

Hashimoto A, Pickard MA (1984) Chloroproxidases from Caldariomyces (= Leptoxyphium) Cultures Glycoproteins with Variable Carbohydrate Content and Isoenzymic Forms. J Gen Microbiol 130 2051... 

The transferrins contain varying amounts of carbohydrates (Table 7) and can be classified as glycoproteins. Williams (136) stated that ovotrans-ferrin and chicken serum transferrin differed only in carbohydrate contents. The ovotransferrin contains no sialic acid (44, 136). Serum transferrin, on the other hand, contains sialic acid. Williams (136), from the results of treating the serum transferrin with the enzyme neuraminidase, suggested that differences in the electrophoretic mobilities and isoelectric points of the multimolecular forms of serum transferrins may be due to differences in their contents of sialic acid. 

Many secretory and membrane proteins are modified in the lumen of the ER. Protein glycosylation, the addition of covalently bound oligosaccharide chains, is a common reaction in the ER lumen and the Golgi complex. Most proteins in the ER lumen destined for secretion from the cell or for transport to other intracellular sites are glycoproteins. The carbohydrate content of glycoproteins can vary from 0.5 to 80% or more of the glycoprotein mass. Glycoprotein structures were described in Chapter 9, and their biosynthesis are covered in Chapter 20. 

Glycoproteins. These are combinations of carbohydrates with protein. Usually the amount of carbohydrate is small, but some glycoproteins have carbohydrate contents of 8 to 20 percent. An example of such a mucoprotein is ovomucin of egg white. 

Amine oxidases are homodimers with subunit molecular masses generally in the range 70kDa to 95kDa with one copper ion and one organic cofactor per subunit. Eukaryotic amine oxidases are glycoproteins with carbohydrate contents estimated at 3nl0%. Further information on the protein chemistry of amine oxidase can be found in Knowles Yadav (1984) and Pettersson (1985). 

The observed heterogeneity can be ascribed to the fact that He s are glycoproteins. Typically, molluscan He s have a carbohydrate content of 8-10%, compared to 1-4% for arthropodan He s. 

MPO is a covalently linked dimeric glycoprotein of Mr 140 kDa comprised of 745 amino acids. MPO consists of three different isoenzyme forms termed a, b, and c. The natme of the chemical differences between these isoforms is not fiilly understood, and only isoform c has been crystallized. Catalytically active recombinant human MPO has been expressed in Chinese hamster ovary cells. However, incomplete posttranslational processing of the recombinant enzyme yields a monomeric form of the enzyme consisting of a single polypeptide chain of Mr 84 kDa with altered carbohydrate content. ... 

The glycoprotein ceruloplasmin is a monomeric enzyme with a molecular mass of about 130 kDa and 1000 amino-acid residues. The carbohydrate content has been determined to be 10% and an acidic isoelectric point of 4.4 for human ceruloplasmin has been reported. 

Human leukocyte elastase (HLE EC 3.4.21.37 also known as human neutrophil elastase, HNE) [1] is a strongly basic glycoprotein which is produced by polymorphonuclear leukocytes (neutrophils) and is released from their azurophilic granules [2]. HLE exists as at least four distinct isozymes, which range in molecular weight from 24 [3] to 30 kDa [4] and appear to differ only in carbohydrate content [5]. Furthermore, human sputum elastase (HSE), which is isolated from purulent sputum as at least five distinct isozymes [6], is both immunologically and catalytically indistinguishable from HLE [7] and is believed to be identical to it. 

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