Studies on the heparin sulphamidase activity from rat spleen. Intracellular distribution and characterization of the enzyme

A sulphamidase activity present in rat spleen capable of hydrolysing N-[(35)S]sulphated heparin was studied. This activity was associated with the lysosomal fraction. Studies in vivo showed that the rat is capable of significantly desulphating heparin. Lysosomes in all the major tissues can effectively accumulate heparin. The heparin sulphamidase and arylsulphatase activities from rat spleen were separated by isoelectric focusing. Heparin sulphamidase was a distinct entity from all the arylsulphatase activities.     

The specific assay of arylsulphatase C, a rat liver microsomal marker enzyme

Conditions based on previous assays with potassium p-acetylphenyl sulphate have been established for the specific assay of arylsulphatase C in rat tissues. The enzyme has optimum activity with 40mm substrate at pH8.0 in the presence of 0.1m-phosphate buffer. Under these conditions arylsulphatase C can be assayed without interference from the other arylsulphatase enzymes present and is useful as a marker for the endoplasmic reticulum in cell-fractionation studies.     

Relative distribution of arylsulphatases A and B in rat liver parenchymal and other cells

The relative activities of arylsulphatases A and B were measured in rat liver parenchymal and non-parenchymal cells, in peritoneal macrophages and in a number of rat tissues. Although absolute values cannot be obtained, it was shown that the arylsulphatase B/arylsulphatase A activity ratio is much higher in non-parenchymal cells than in parenchymal cells. The ratios in adrenals, brain and testis are very similar to each other but differ from those found in spleen, kidney and liver. These ratio variations may be caused by alterations in the activity of the B enzyme rather than the A enzyme. The relatively high B enzyme/A enzyme ratios in all rat tissues explains why the method devised for the independent assay of human arylsulphatases A and B cannot be employed with rat tissues.     

THE REGIONAL DISTRIBUTION, AGE DEPENDENT VARIATION AND SPECIES DIFFERENCES OF BRAIN ARYLSULPHATASES

Abstract— The relative proportions of arylsulphatase A and B were determined by the method of B aum , D odgson and S pencer (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 K _m 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.     

The intracellular distribution of arylsulphatase C and oestrogen sulphatase activities in rat kidney and spleen.

The arylsulphatase C of rat kidney and spleen is localized predominantly in the microsomal fraction. The distribution pattern is paralleled by that of oestrogen sulphatase, as in rat liver. The general usefulness of arylsulphatase C as a microsomal marker enzyme is indicated.     

Combined histochemical and biochemical investigation to the reliability of the demonstration of arylsulphatase activity in cryostat sections

Summary The reliability of the enzyme histochemical technique, for the demonstration of arylsulphatase activity, using 6-bromo-2-naphthylsulphate as a substrate, is biochemically tested by using partly purified lysosome and microsome preparations from fresh human placenta tissue. Microsomes from frozen placenta with an arylsulphatase deficiency and lysosomes from rat liver, are also investigated. For the biochemical test methods, 6-bromo-2-naphthylsulphate and p-nitrocatecholsulphate are used as substrates. Under similar reaction conditions, varying the pH of the incubation medium and adding inhibitors or activators, the histochemical and biochemical reactions are compared. The results of this study whow that the enzyme histochemical technique — except for some limitations — is suitable for the demonstration of microsomal arylsulphatase in cryostat sections.     

Autophagy-related changes of arylsulphatases A and B in rat liver lysosomes.

The total arylsulphatase activity and the relative activities of lysosomal arylsulphatases A and B were measured in the liver of control rats and rats subjected to treatments that provoke hepatic autophagocytosis. The total liver arylsulphatase activities were increased in starved and starved glucagon-treated rats, but not in sham-operated and hepatectomized rats. Arylsulphatases A and B in the mitochondrial-lysosomal (M-L) fraction were separated by polyacrylamide-gel electrophoresis at pH 8.8; they were made visible by incubating the gels with p-nitrocatechol sulphate as substrate, and measured by quantitative densitometry. In untreated controls, arylsulphatases A and B comprised 41.4 +/- 0.5% and 58.6 +/- 0.5% of the total arylsulphatase activity respectively; the arylsulphatase A/arylsulphatase B activity ratio was 0.71. All experimental treatments produced a significant decrease in the percentage of lysosomal arylsulphatase present as the A form and an increase in that present as the B form, and the activity ratio of arylsulphatase A/arylsulphatase B declined. The magnitude of these changes increased in the following direction: starvation for 24h=sham hepatectomy less than glucagon + starvation less than subtotal hepatectomy. These results indicate that the arylsulphatase A/arylsulphatase B activity ratio in liver lysosomes of normal rats is maintained within rather narrow limits, and this ratio declines during enhanced autophagocytosis. These findings, together with observations that suggest that arylsulphatase B may be a partially degraded form of arylsulphatase A, are consistent with the view that the A form is more rapidly converted into the B form during autophagy, owing to the digestive activity of the other lysosomal hydrolases present in autophagic vacuoles.     

The development of arylsulphatase in the small intestine of the rat

1. Arylsulphatase activity was measured in stomach, proximal and distal third of small intestine, colon, liver and kidney of foetal and neonatal Sprague-Dawley rats and Swiss mice, with nitrocatechol sulphate as substrate. 2. The specific activity in the distal small intestine, but not in the stomach, proximal small intestine or colon, increased about fourfold between 5 and 16 days after birth in both conventional and germ-free rats. 3. No comparable increase occurred in the distal small intestine of the mouse. 4. The specific activity of acid phosphatase in the distal small intestine of the rat rose only slightly when the arylsulphatase activity increased. 5. The pH optimum and Michaelis constant of arylsulphatase activity of the distal small intestine were similar for 1-day-old, 9-day-old and adult rats. 6. When extracts of distal small intestine of 1-day-old and 9-day-old rats were incubated together, the arylsulphatase activities were additive.     

Combined histochemical and biochemical investigation to the reliability of the demonstration of arylsulphatase activity in cryostat sections.

The reliability of the enzyme histochemical technique, for the demonstration of arylsulphatase activity, using 6-bromo-2-naphthylsulphate as a substrate, is biochemically tested by using partly purified lysosome and microsome preparations from fresh human placenta tissue. Microsomes from frozen placenta with an arylsulphatase deficiency and lysosomes from rat liver, are also investigated. For the biochemical test methods, 6-bromo-2-naphthylsulphate and p-nitrocatecholsulphate are used as substrates. Under similar reaction conditions, varying the pH of the incubation medium and adding inhibitors or activators, the histochemical and biochemical reactions are compared. The results of this study show that the enzyme histochemical technique--except for some limitations--is suitable for the demonstration of microsomal arylsulphatase in cryostat sections.     

Improvements in the method for the electron microscopic localization of arylsulphatase activity

Summary The optimal conditions for the demonstration of arylsulphatase activity in the proximal convoluted tubule cells of the rat kidney were studied at light and electron microscopic level. 8-hydroxyquinoline sulphate, p-nitrophenyl sulphate and 2-hydroxy-5-nitrophenylsulphate were used as substrates and barium and lead as capturing ions. The effect of fixation, capturing ions, substrate concentration and pH was studied biochemically. The results of these biochemical studies were then verified histochemically. Finally a recommended method for the light and electron microscopic demonstration of arylsulphatase activity was presented.     

Studies on the meta and para O-sulphation of the catechol compound 3,4-dihydroxybenzoic acid by rat liver sulphotransferase in vitro.

The enzymic meta and para O-sulphation of 3,4-dihydroxybenzoic acid was investigated in vitro with a dialysed high-speed supernatant from rat liver. The O-sulphated products were identified by comparison with the reference compounds. The chemical synthesis and identification of the reference O-sulphate esters is described in detail. The sulphotransferase activity of the dialysed supernatant from rat liver towards 3,4-dihydroxybenzoic acid was 580 pmol of 3-O-sulphate and 120 pmol of 4-O-sulphate formed/min per mg of protein at the optimal pH of 7.4. The meta/para ratio of O-sulphation was independent of pH, time of incubation, concentration of enzyme and presence of dithiothreitol. The O-sulphate esters of 3,4-dihydroxybenzoic acid were found to be good substrates for the arylsulphatase reaction at pH 5.6. The arylsulphatase activity of a dialysed preparation from rat liver was 4.0 nmol of 3-O- and 5.7 nmol of 4-O-sulphate ester hydrolysed/min per mg of protein, respectively. Arylsulphatase from Helix pomatia had an activity of 620 pmol of 3-O-sulphate and of 16.6 nmol of 4-O-sulphate ester hydrolysed/min per unit (mumol/h) of sulphatase.     

Effects of acute and chronic administration of ethanol on rat brain arylsulphatase A and B

Acute (4g/kg i.p.) and chronic (Sustacal^TM diet containing 10% ethanol for 20 days) administration of ethanol to male Sprague-Dawley rats produced no change in the content or enzyme activity of brain arylsulphatase A. In contrast to the lack of effect on arylsulphatase A, the acute and chronic administration of ethanol resulted in an increase in the activity of brain arylsulphatase B (15.8% and 18.4%, respectively). However, the enhancement of the activity of arylsulphatase B was observed only in the brain homogenates which were subjected to osmotic shock. No enhancement of the arylsulphatase B activity was found in the supernatant soluble fraction after the acute and chronic administration of ethanol. Furthermore, acute and chronic ethanol administration did not alter the activities of arylsulphatase A and B in microsomes which have been suggested as sites of the synthesis of lysosomal hydrolases. In addition, 80 mM ethanol, in vitro, did not affect the activity of arylsulphatase A and B. The results of the present study suggest that the acute or chronic administration of ethanol might enhance the activity of lysosomal membrane bound arylsulphatase B via altering the lipid metabolism of lysosomal membranes.     

THE PATTERNS OF ARYLSULPHATASES A AND B IN HUMAN NORMAL AND METACHROMATIC LEUCODYSTROPHY TISSUES AND THEIR RELATIONSHIP TO THE CEREBROSIDE SULPHATASE ACTIVITY

Abstract— The arylsulphatase A and B patterns of human tissues and leucocytes have been established by isoelectric focussing. Assay conditions, which enable an evaluation of these patterns as quantitatively as possible, have been studied. The dependences of the enzyme patterns on the origin of the tissues and on the storage conditions have been determined. The arylsulphatase A obtained by isoelectric focussing exhibits cerebroside sulphatase activity in the presence of detergents. A purified preparation of the arylsulphatase B likewise shows a significant, although low, cerebroside sulphatase activity. In cases of the conventional types of metachromatic leucodystrophy the arylsulphatase A activity is missing, while in an atypical form of this disease ('ML Variant' according to A ustin et al . (1965) the arylsulphatase A, B and C activities are deficient. In both forms, however, residual activities of the deficient enzymes could be detected which showed isoelectric points identical to those of the normal enzymes.
The following nomenclature is proposed: 'Variant B' for the conventional type, in which the arylsulphatase B activity is present, and 'Variant O' for the exceptional cases, in which all arylsulphatase activities are deficient. The significance of the cerebroside sulphatase activity of arylsulphatase B for a possible residual turnover of cerebroside sulphates in the conventional type of the disease is discussed.     

Arylsulphatase activity and cerebroside sulphates in the frog oviduct during the reproductive cycle

Summary The presence of arylsulphatase A and cerebroside sulphates in different tracts ofRana esculenta oviduct during different phases of the reproductive cycle were investigated by histochemical and biochemical procedures. The results indicate that enzyme activity shows seasonal fluctuations connected with the phase of the sexual cycle. The concentrations of cerebroside sulphates (the natural substrates of arylsulphatase A) is related to the activity of this hydrolytic enzyme. The role of arylsulphatase A activity in regulating the substrate concentration, and particularly that of sulphatides, is discussed.     

Histochemical localization of the soluble arylsulphatase activities in rat brain

Summary The modified method of Goldfischer has been used for the localization of soluble arylsulphatase activities in the rat brain. The highest activity of these enzymes was found in some parts of the drive system and in nervous tracts. The bulk of activity in neurons and glial cells is localized in the lysosomes. Some arylsulphatase activity has been found to be bound to myelin sheaths. We have not been able to ascribe this activity to any defined subcellular structures, by light microscopy.The method of Goldfischer does not permit differentiation of the two soluble arylsulphatases (enzymes: A and B). We suggest however, that these enzymes may have different functions in the brain. Arylsulphatase A (cerebrosidesulphatase) may be primarily connected with the nervous tracts, a hypothesis supported by the character of disorders caused by lack of this enzyme in metachromatic leucodystrophy. Arylsulphatase B, hydrolysing sulphuric esters of catecholamines, may be involved in the function of the drive system.Arylsulphate sulphohydrolase, EC 3. 1.6. 1.     

Purification of soluble arylsulphatases from ox brain

1. Two soluble arylsulphatases (A and B) have been extracted from ox brain by a modified Albers autolysis method and purified by acetone and ammonium sulphate precipitation and dialysis. 2. A 1600-fold purification was achieved with arylsulphatase A and 320-fold purification with arylsulphatase B. 3. The specific activity of arylsulphatase A was 266000 4-nitrocatechol units/mg. of protein N, and that of arylsulphatase B was 64600units/mg. of protein N. 4. Arylsulphatase A seems to be electrophoretically homogeneous. 5. With 3mm-dipotassium 2-hydroxy-5-nitrophenyl sulphate as substrate the optimum pH for the activity of arylsulphatase A was 4.7, and for arylsulphatase B it was 6.1 with a 60mm solution of the same substrate.     

Arylsulphatases in the rabbit oviduct: postovulatory changes tested by histochemical and biochemical procedures

Summary A histochemical and biochemical study of the activity of arylsulphatases A and B was carried out on the oviduct of female rabbits during the first days after mating. The histochemical results demonstrated that the ampullary and the isthmic epithelial cells have a positive reaction to the sulphatases during the whole of the postovulatory period tested. The enzymatic activity is mainly localized in the basal cellular cytoplasm. The biochemical results confirmed that both arylsulphatase A and B are active. Arylsulphatase A activity is more intense in the ampulla than in the isthmus and it increases during the whole of the postovulatory period; in the isthmus the activity increases up to 72 h, thereafter decreasing again. The arylsulphatase B activity is always lower than arylsulphatase A activity; maximum activity is reached between 66 to 72 h after mating. The arylsulphatase B is relatively higher in the ampulla than in the isthmus. The biological role of these enzymes is discussed in relation to the regulation of the sulphated glycoconjugates.     

Enzymic heterogeneity of adrenocortical lysosomes: an X-ray microanalytical study

Summary The enzymic heterogeneity of the lysosomal system has been demonstrated earlier. This study was concerned whether or not the lysosomes of the two outer zones of the rat adrenal cortex reveal any population characteristics on the basis of the activity of two enzymes. A double incubation method was used for the simultaneous electron cytochemical demonstration of acid phosphatase and arylsulphatase activity in the zonae glomerulosa and fasciculata of the adrenal. Lysosomes in semi-thin (0.5m) or ultra-thin sections were analysed with an ORTEC energy-dispersive X-ray microanalyser mounted on a JEOL TEMSCAN-100 C electron microscope.Linearity of the amount of reaction deposit with incubation time was found for both enzymes. On the basis of the proportion of the two reaction products in individual lysosomes, three populations were distinguished. One with high acid-phosphatase and low, if any, arylsulphatase activity was only present in the zona glomerulosa. The other two populations exhibited stronger or weaker prevalence of arylsulphatase activity and were common in both zones. The values of the Ba/Pb ratio characteristic of each population changed with the reaction sequence but the principal distribution pattern did not. The nature of the interaction between the two reactions, as well as the possible functional significance of the lysosomal populations in the adrenal cortex, are discussed but are not yet clarified.     

Studies of the oestrogen sulphatase and arylsulphatase C activities of rat liver

Detailed studies on the hydrolysis of p-acetylphenyl sulphate and oestrone sulphate by rat liver preparations strongly indicate that arylsulphatase C and oestrogen sulphatase are the same enzyme. Liver is the richest source of both enzymes, which have identical intracellular distributions, being localized mainly in the microsomal fraction. Low oestrogen sulphatase and arylsulphatase C activities were present in foetal liver and these increased at a similar rate after birth. The activities of the enzymes in an ethionine-induced hepatoma were similarly low. Results of heat inactivation, mixed-substrate and competitive-inhibition experiments employing liver microsomal fractions were also consistent with one enzyme being involved. Oestradiol-17beta 3-sulphate was also hydrolysed by microsomal preparations and activity towards both this substrate and oestrone sulphate was inhibited by oestrone and oestradiol-17beta. The physiological significance of this inhibition is discussed.     

Catalytic and immunochemical properties of arylsulphatase A from urine, modified by potassium ferrate

Arylsulphatase A (EC 3.1.6.1.) from urine was inactivated with potassium ferrate, a strong oxidizing agent. The inhibition could be prevented by competitive inhibitors, tetraborate and orthophosphate. Tetraborate which was shown to be a powerful competitive inhibitor (determined Ki = 4 X 10(-5) M) gave more efficient protection. The partially inactivated enzyme exhibited a Km value similar to that of the unmodified arylsulphatase A, and its Vmax decreased in proportion to the loss of enzymatic activity. The partially modified enzyme did not lose its ability to catalyse hydrolysis of p-nitrocatechol sulphate according to the "anomalous kinetics" exhibited towards this substrate and characteristic for arylsulphatase A. The immunochemical properties of arylsulphatase A either fully or partially inactivated were similar to those of the native enzyme. The results allow to conclude that ferrate reacts with arylsulphatase A in its active site. Thus ferrate seems to be a very sensitive probe for amino acid residues essential for catalytic activity of arylsulphatase A.