The chemistry of heparin

Abstract

HEPARIN, the anticoagulant discovered by Howell [1918], has not until recent times been readily accessible either to the research chemist or to the physiologist. Its high price has prevented a thorough study of its chemical properties and its more extensive use in physiological laboratories and in clinical practice. Thanks to the recent work of Charles and Scott [1933], fresh possibilities have been afforded in both directions. Heparin has been shown to be a common tissue constituent, and the method of its preparation has been greatly improved.As to the chemical nature of heparin, very little is known. Howell [1928] found a hexuronic acid in his purest preparations. Schmitz and Fischer [1933] described highly purified preparations, which they believed to consist of a trisaccharide, C18H320.7, containing one carboxylic group. Charles and Scott found a positive oa-naphthol reaction, but the test for hexuronic acids with naphthoresorcinol was negative. Consequently the authors agree only in one respect, namely as to the occurrence of carbohydrate groups in the heparin preparations. Furthermore, there is disagreement as to the nitrogen content of the preparations. Howell found at an early stage of the preparation that the sodium cyanide test of Lassaigne proved negative, and he gives no further information as to the nitrogen content. Nor do Schmitz and Fischer pay any attention to this question. On the contrary Charles and Scott found about 2 % of nitrogen in their purest preparations, which were as pure as any hitherto prepared. Another finding in the papers of these investigators is also remarkable, namely the high ash content of the heparin samples. Howell found 37 % and Charles and Scott about the same figure. Schmitz and Fischer, who found a certain amount of ash even in the crystalline brucine salt, repeatedly discuss the possibility of molecular combination between heparin and neutral salts.This divergence of opinion as to the composition of heparin preparations seemed to justify a reinvestigation. The author therefore prepared heparin from ox and horse liver, following the principles outlined by Charles and Scott. Only in some details was their technique modified. The crude material obtained after tryptic digestion proved to be 2 or 3 times more active than the commercial preparations. After treatment with Lloyd's reagent 2 or 3 times as recommended by Howell, no considerable further purification seemed possible. Several attempts to fractionate the preparations with barium acetate, barium hydroxide, lead acetate (basic) and glacial acetic acid did not result in more active products. In this state of purity the samples did not precipitate in aqueous solution with lead acetate or with cadmium chloride. As further purification seemed impossible, the samples were submitted to analysis.Analysis of the heparin preparations. The different preparations of heparin seemed to be of a rather uniform chemical composition (see Tables I and II). Furthermore the content of ash, 38-41 %, and of nitrogen, 1-63-1'84 %, corres...

Cytochemical Variations in the Granules of Rat Mast Cells, and Their Relation to Mast Cell Maturation

“…the heparin was sulphated, it remained to provide evidence of the degree of sulphation. Jorpes and Gardell (1948) showed tliat heparin monosulphuric acid was P.A.S. positive and it was further established that the more highly sulphated forms were P.A.S.…”

“…positive and it was further established that the more highly sulphated forms were P.A.S. negative (Charles and Totld, 1940;jorpes, Werner and Aberg, 1948;Coniori, 1952). The P.A.S.…”

“…Lison (1935Lison ( , 1936 claimed that metacliromatic staining with toluidine blue was a specific bistochemical method for the demonstration of sulphated mucopolysaccharides in the mammalian organism. It is now well established that tlie metachromatie granules of mast cells contain heparin and it has been claimed that the degree of heparin metachromasia is proportional to the number of sulphate groups with which the heparin molecule is esteriBed (Lison, 1935;Jorpes, 1946;Riley, 1953). Riley (1955) believed the preci.se histochemical significance of mt'tachromasia was not established but it had been amply confirmed that tlie progressive metachromasia whieh accompanies mast ceil maturation was an inde.x of the extent to which sulphation had occurred.…”

“…The P.A.S. reaction has been applied ln'stologically to mast cells and Jorpes et al (1948) found that positive reactions were obtained in mast cells of the subcutaneous tissues from young rats. These findings were interpreted as evidence for the presence of heparin monosulphuric acid or some t)ther heparin precmsor.…”

Expressão e caracterização das quimases recombinantes específicas de mastócitos de camundongos (mMCP4 e 5)

“…Nesta época a composição química dos grânulos era desconhecida e não se sabia qual o componente granular reagia com corantes a base de anilina. Atualmente, sabe-se que a metacromasia dos mastócitos é devido à interação dos corantes básicos (catiônicos) com os resíduos ácidos (aniônicos) das cadeias de glicosaminoglicanas (GAGs) sulfatadas (heparina e sulfato de condroitina) da proteoglicana serglicina, presente em abundância nos grânulos destas células (JORPES, 1935;RANSON;GALLAGHER, 1992;ABRINK et al, 2004). Atualmente, os mastócitos são identificados como células multifuncionais residentes no tecido conjuntivo (RIBATTI & CRIVELLATO, 2014;DA SILVA, et al, 2014).…”