Heparin macromolecule

The molecular mass of heparin varies between 10000 and 30000, depending on the source of its isolation13). Since the above formula of heparin gives only the approximate presentation of the structure of its macromolecule, let us examine the data concerning functional groups and other components of the heparin macromolecule. 

All the synthesized HC copolymers were negatively charged, as only the part of the negatively charged groups of the heparin macromolecule is involved in the reaction with the quaternized ammonium groups, while the other remain unneutralized. 

Heparin immobilized using the described procedure retained only 1 % of the initial activity of heparin in solution. This fact may probably be explained by the denaturation of heparin effected by nitric acid, which was the reaction medium for the graft-copoly-merization procedure. The inaccessibility of the majority of heparin macromolecules of a copolymer not swelling in an aqueous solution, in particular, supplies... 

Polymeric carbohydrates are usually encountered as distributions, so high resolution is rarely important. Of all biological macromolecules, carbohydrates are particularly amenable to analysis by GPC because hydrophobic interactions are typically weak. A section below is devoted to the analyses of carboxymethylcellulose and xanthan. Other examples of polysaccharides of interest are hyaluronic acid,62 polymers of (l-glucose,121125 heparin,126127 cellulose and chitin,128 and Mucorales extracellular polysaccharides.129... 

The possibility of detecting polyionic macromolecules added a new thrust to the area of ion-selective electrodes in the past decade. Professors Ma and Meyerhoff from the University of Michigan described in their pioneering work [35] the first polymeric membrane electrodes that respond to the polyanion heparin. 

Biomolecules - Other types of molecules and macromolecules are active during the immune response. Histamine and serotonin were encountered in our discussion of the nervous system. They are factors which act to intensify the response to a nonself presence. Heparin, the anticoagulant. 

The stability of heparin-amine complexes depends to a large extent on the structure of the constituent amine. The best results were obtained for dimethylaniline and pyridine (Table 6) 65). The amount of bound heparin is, as is seen, proportional to the amount of immobilized amine, while the molar ratio amine/heparin is predetermined by the structure of the surface. Microscopically rough surfaces were shown to prevent association between heparin and amine as the portion of the amine is sterically inaccessible for the macromolecules of heparin. 

Thus, the activity of immobilized heparin is effected most by the mobility of its macromolecule and its accessibility for physiological substrates 96,97). These parameters may easily be controlled by changing the structure of the hydrophilic gel and... 

Table 20 presents the results pertaining to the synthesis and properties of the gels. The gels are seen to sorb heparin from plasma solution. Their capacity (the maximal amount of heparin sorbed) increases as the mobility and accessibility of the cholesterol fragment for the macromolecules of heparin is increased by varying the length of the polymethylene spacer. The data in Table 20 illustrate that the capacity varies from 0.7 to 0.9 and 1.3 mg/mg of immobilized UChD for cholesterol esters of N-meth-acryloyl-fS-alanine (n — 2), N-acryloyl-co-aminoenantic acid (n = 6), and N-meth-acryloyl-co-aminolauric acid (n = 11), respectively. 

In the late 1960s, Engel and coworkers [56-58] proposed sulfated and sulfonated surfactants as absorption promoters for two biological macromolecules, heparin and insulin. In these studies, sodium lauryl sulfate (SLS) promoted the absorption of heparin but not of insulin intraduodenally administered in rats and dogs. 

During the past few decades, a number of important studies were published on the effect of cholic acid derivatives on the absorption of macromolecules [81]. Guarini and Ferrari [84—86] compared simultaneous oral dosing of NaDOC and heparin to pretreatment with NaDOC by oral gavage in dogs followed by oral heparin administration at a 0.5-24-h interval. In all pretreatment regimens, NaDOC enhanced heparin absorption, with the maximum effect observed when heparin was administered 1 h after NaDOC. 

Tokunaga, Y., S. Muranishi, and H. Sezaki. 1978. Enhanced intestinal permeability to macromolecules. I. Effect of monoolein-bile salts mixed micelles on the small intestinal absorption of heparin. J Pharmacobiodyn 1 28. 

No Heparin Heparin normally occurs as a macromolecule complexed with histamine in mast cells where its physiologic role is unknown. It is extracted for commercial use from porcine intestine or bovine lung. Heparin is a mixture of straight-chain anionic glycosaminoglycans... 

Stmctural investigations of the anticoagulant macromolecule heparin (VII) currently favour a linear polydisaccharide. 

Interactions between dmgs and ionic macromolecules are another potential source of problems. Heparin sodium and erythromycin lactobionate are contraindicated in admixture, as are heparin sodium and chlorpromazine... 

---