Isolation and characterization of glycosaminoglycans in human brain of different age groups

Five distinct glycosaminoglycan fractions have been isolated from human brain of various age groups, by employing an improved fractionation procedure. Analysis of these fractions showed that human brain contains hyaluronic acid, chondroitin-4-sulphate, chondroitin-6-sulphate, dermatan sulphate, heparan sulphate and two unidentified low sulphated fractions. The pattern of variation of these compounds with age, indicates that they may be playing an important role in the process of myelination and brain maturation

The regional distribution, age dependent variation and species differences of brain arylsulphatases

The relative proportions of arylsulphatase A and B were determined by the method of Baum, Dodgson and Spencer (1959) in brains of various animal species and it was found that there was a considerable variation in the concentration of these two enzymes. Arylsulphatase A and B of various animal species including rat, man, monkey, sheep and chicken were partially separated using zinc acetate fractionation procedure and gel electrophoresis. The chicken brain arylsulphatase A had a similar electrophoretic mobility to that of arylsulphatase B of other species. Further, chicken brain arylsulphatase A precipitated at a zinc acetate concentration of 0005 M, a condition under which arylsulphatase B from the brain of other species precipitated. Kinetic properties such as Km value and inhibitory effect of sulphite and phosphate ions indicated that chicken brain arylsulphatase A was similar to arylsulphatase A of other species. The results on regional distribution of arylsulphatase A and B activities in monkey brain and in developing rat brain suggest a relationship between arylsulphatase A and sulphatides and arylsulphatase B and mucopolysaccharides

Enzymic studies on sulphatide metabolism in different stages of experimental allergic encephalomyelitis

The activities of three enzymes-cerebroside sulphotransferase, 3'-phospho-adenosine 5'-phosphosulphate synthesizing enzyme and arylsulphatases A and B have been studied in various developmental and recovery stages of experimental allergic encephalomyelitis. The concentrations of cerebroside and sulphatide were also analysed during these stages. It was observed that the sulphatide concentration decreased during the development of the disease, with a concurrent increase in the activity of arylsulphatase and vice versa during the recovery stages. 3'-Phosphoadenosine 5'-phosphosulphate synthesis as well as sulphotransferase activity increased during the pre-acute stage of the disease, reached a maximum at the acute stage and decreased during recovery stages

Enzymatic desulphation of cerebroside-3-sulphate by chicken brain arylsulphatase A

In earlier work from this laboratory it was shown that arylsulphatase of chicken brain resembles arylsulphatase A of other animal species in several of its properties but exhibits certain characteristics similar to that of arylsulphatase B (Farooqui and Bachhawat, 1971). Recently the arylsulphatase A of chicken brain was purified and it was demonstrated that the purified enzyme could desulphate cerebroside-3-sulphate also (Farooqui and Bachhawat, 1972). In the present report we have made a study of the kinetic properties of this unique arylsulphatase A purified from chicken brain using p-nitrocatechol sulphate and cerebroside-3-sulphate as substrates

Purification and properties of brain alkaline phosphatase

Alkaline phosphatase from sheep brain has been purified to homogeneity. The method includes butanol extraction, fractional ethanol precipitation, ion-exchange chromatography on DEAE-cellulose, and on DEAE-Sephadex followed by Sephadex G-200 filtration. By these steps, the enzyme is purified 22,920-fold with 15% recovery. The homogeneous enzyme is shown to be a sialoglycoprotein in nature. Neuraminidase treatment reduces the electrophoretic mobility of the enzyme. The enzyme shows pyridoxal phosphate phosphatase activity along with p-nitrophenylphosphate phosphatase activity. Both these compounds behave as mutual alternate competitive substrates. The general properties of the enzyme are described

The nature of sulphation of uronic acid-containing glycosaminoglycans catalysed by brain sulphotransferase

A sulphotransferase system of rat brain catalyses the transfer of sulphate from 3'-phosphoadenosine 5'-phosphosulphate to the low-sulphated glycosaminoglycans isolated from normal adult human brain. These were shown to be precursors of higher-sulphated glycosaminoglycans by DEAE-Sephadex column chromatography and paper electrophoresis. Nitrous acid degradation and mild acid hydrolysis of enzymically-sulphated fractions further confirmed the presence of heparan sulphate in human brain. A partially purified sulphotransferase preparation was obtained from neonatal human brain using chondroitin-4-sulphate as sulphate acceptor. This sulphotransferase catalyses the transfer of sulphate to the various uronic acid containing glycosaminoglycans. Heparan sulphate was the best sulphate acceptor followed by dermatan sulphate, N-desulphoheparin, chondroitin-4-sulphate and chondroitin-6-sulphate in decreasing order. Sulphotransferase obtained from 1-day-old rat, rabbit and guinea pig brain also had the same pattern of specificity towards various sulphate acceptors. This sulphotransferase catalyses both N-sulphation and O-sulphation. Studies on the sulphotransferase obtained from both rat and human brain of various age groups indicate that the ratio of N-sulphation: O-sulphation decreases as the brain matures

Isolation and characterization of glycosaminoglycans from brain of children with protein-calorie malnutrition

The uronic acid containing glycosaminoglycans (GAGs) were isolated from the brains of 1-year-old and 4-year-old kwashiorkor children and characterised by constituent analyses. A marked reduction is the total GAG concentration of brain was noticed in both cases of kwashiorkor. In the 1-year-old kwashiorkor brain, hyaluronic acid is the most predominant GAG (73.5 per cent) whereas heparan sulphate, chondroitin sulphates and low sulphated chondroitin sulphate constituted less than 10 per cent. In the 4-year-old kwashiorkor brain, the proportion of hyaluronic acid was 27.5 per cent, low sulphated chondroitin sulphate 31.2 per cent, chondroitin sulphates 28.3 per cent and heparan sulphate 10 per cent. This marked reduction in the concentration as well as qualitative changes in GAG in protein-calorie malnutrition as compared to the normal is discussed in relation to brain function

Sulphate metabolism in acute EAE rats using isolated brain perfusion technique

Metabolism of glycolipids and glycosaminoglycans were studied in rats in the acute stage of experimental allergic encephalomyelitis (EAE) using isolated brain perfusion technique. It was observed that there was a significant decrease in the concentration of cerebroside, sulphatide and GAG (hyaluronic acid and low sulphated GAG) when compared to normal and pairfed control rats. The radioactive sulphate incorporation into the cerebroside sulphate and sulphated GAG was significantly higher in the case of rats in the acute stage of EAE than the normal and pairfed control rats

Increased circulatory half-life of liposomes after conjunction with dextran

Dextran was covalently coupled to neutral unilamellar liposomes. Dextran conjugated liposomes were cleared from the circulation at a much slower rate than unconjugated liposomes. The uptake of dextran conjugated liposomes by liver and spleen was also decreased. The amount of dextran on the surface of liposomes was found to be a determining factor for their stability in circulation. Dextran conjugated liposomes therefore may be a more effective way of controlled drug release

Isolation and characterization of glycosaminoglycans in brain of different species

The uronic acid-containing glycosaminoglycans present in the brains of rat, monkey, chicken, sheep and rabbit were isolated into various fractions by combining the cetyl pyridinium procedure and DEAE-Sephadex column chromatography. The analyses of the fractions show that hyaluronic acid, chondroitin-4-sulphate, chondroitin-6-sulphate, heparan sulphate and a testicular hyaluronidase-resistant galactosamine-containing GAG are present in the brain of all the species studied. Hyaluronic acid is the major GAG (33-41 per cent). Chondroitin-4-sulphate (19-35 per cent), and heparan sulphate (11-19 per cent), are the next prominent GAGs, in all the species except chicken. The results indicate the similarity in the pattern of GAGs in the brain of all the species