Steroid sulphatase, arylsulphatase and beta-glucuronidase in the Mollusca

Measurement of the arylsulphatase of Patella vulgata with 4-methylumbelliferone sulphate

1. The preparation, purification, chemical and spectral properties of potassium 4-methylumbelliferone sulphate are described. 2. The use of 4-methylumbelliferone sulphate as a substrate for the arylsulphatase of Patella vulgata is presented with specific reference to the fluorimetric assay procedure used with this substrate. 3. 4-Methylumbelliferone sulphate is compared with the previously used synthetic sulphatase substrates nitrocatechol sulphate and p-nitrophenyl sulphate with respect to K(m), V(max.) and sensitivity in the assay of arylsulphatase. 4. 4-Methylumbelliferone sulphate was strongly inhibited by phosphate. Sulphate, a less potent inhibitor, appeared to be of the competitive type with some anomalous characteristics.

Localization and distribution of alkaline phosphatase activity in the hepatopancreas of the snail

Histocytochemical methods were used to investigate alkaline phosphatase activity in the digestive gland (hepatopancreas) of the common garden snail Helix aspersa. Histochemical findings and light microscopic observations showed that enzymatic activity was confined mainly to the basal connective tissue that enveloped the adenomeres. Transmission electron microscopy showed that enzymatic activity was localized in the plasma membrane, and showed an intercellular distribution along the lateral surfaces and the basal portions of the cells in different adenomeres. Alkaline phosphatase activity was also found in the plasma membrane of fibrocytes of the basal connective tissue enveloping the adenomeres. Enzymatic activity was seen around the fat droplets of glandular cells. The possible involvement of alkaline phosphatase in processes or remodelling of the basal connective tissue that envelopes the gland is discussed.

Phosphatase activity in the hepatopancreas of Helix aspersa

1. Phosphatase acid (PhA) activity in the digestive gland (hepatopancreas) of the common garden snail Helix aspersa has been investigated using cytochemical methods. 2. All the cells composing this gland show PhA activity, the distribution pattern differing according to the cell type. 3. The digestive cells show the most widely distributed reaction product (brush border, phagolysosomes, multivesicular bodies and autophagic vacuoles). 4. In the excretory cells this activity appears in large sacs, while in the calcium cells the reaction product is abundant in the calcium granules. 5. Cellular digestion processes performed by each of these cell types is discussed together with their role in the detoxification of heavy elements derived from the environment.

Purification and characterization of sulfatases from Haliotis rufescens: evidence for changes in synthesis and heterogeneity during development

The digestive glands of many marine molluscs are rich sources of arylsulfatase enzymes which may function in the catabolism of sulfated polysaccharides in the diets of herbivorous species. Arylsulfatases, partially purified from the hepatopancreas of the red abalone, Haliotis rufescens, were investigated with respect to heterogeneity, catalytic requirements, and timing of induction during development. Four hepatopancreatic enzymes were purified from adult animals using a combination of hydrophobic interaction and anion-exchange chromatography. Zymograms of the four partially-purified enzymes produced by electrophoresis under nondenaturing conditions revealed a fifth, relatively more basic isozyme. All four partially-purified enzymes appear to be monomeric, with molecular weights of approximately 43,000 Da each, as measured by gel filtration. The affinities for p-nitrocatechol sulfate, pH optima, and strengths of inhibition by anions displayed by these enzymes are similar to the values reported for other molluscan arylsulfatases. Three of the four enzymes have Km values between 0.8 and 2.0 mM for p-nitrocatechol sulfate; the remaining enzyme (A2) has a Km of 6.7 mM. All four enzymes have pH and temperature optima of 5.5 and 45 degrees C, respectively. Three of the four enzymes have-t 1/2 (50 degrees C) values of 3.5 min; the enzyme A4 has a t 1/2 (50 degrees C) of 8.5 min. A monoclonal antibody directed against form A1b does not cross react with any of the other hepatopancreatic arylsulfatases when assayed by Western blot, confirming the structural heterogeneity of the adult enzymes. Total arylsulfatase activity increases in a biphasic manner during early abalone development, with the first increase occurring early in larval maturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Sulphation causes heterogeneity of gastric mucins

The synthesis of mucus glycoprotein in rat stomach was studied in stomach segments, which were pulse-labelled with both [3H]galactose and [35S]sulphate and chased for various times. The radioactive glycoproteins were analyzed by CsCl centrifugation and by agarose gel electrophoresis. After a pulse-labelling for 15 min with [3H]galactose, a possible intermediate with an Mr of 200,000 and a buoyant density of 1.60 g/ml could be demonstrated. Following chase periods of 1 and 4 h, [3H]galactose and [35S]sulphate were present in glycoproteins with a mean buoyant density of 1.50 g/ml. This is clearly different from the main density of glycoproteins isolated from mucosal scrapings (1.46 g/ml). Another difference is the high electrophoretic mobility on gel electrophoretic analysis of newly synthesized glycoproteins compared to that of the major portion of the glycoproteins from mucosal scrapings. When sulphation of glycoproteins was inhibited by sodium chlorate, electrophoretic mobility and buoyant density both decreased. Sodium chlorate had no effect on glycoprotein synthesis nor on glycoprotein secretion. We conclude from our data that the heterogeneity in electrophoretic mobility and buoyant density can be attributed to a different degree of sulphation of the same glycoprotein.

Simultaneous assay for individual sulphated 3 alpha- and beta-hydroxysteroids in serum using high-performance liquid chromatography combined with 3 alpha- and beta-hydroxysteroid dehydrogenases immobilized on one column

A high-performance liquid chromatographic method for the simultaneous determination of individual sulphated 3 alpha- and beta-hydroxysteroids in serum using 3 alpha- and beta-hydroxysteroid dehydrogenases (3 alpha-HSD and beta-HSD, respectively) immobilized on one column and a fluorimeter to detect the resulting NAD+ to NADH transformation is described. Individual sulphated 3 alpha- and beta-hydroxysteroids in serum are extracted with ethanol, solvolysed with sulphuric acid in ethyl acetate and then separated by high-performance liquid chromatography. The hydroxysteroids thus separated are subsequently mixed with NAD+ and then passed through the column in which the following catalytic reaction occurs: (formula, see text) The detection limits are as low as 0.5-1.0 microgram/dl for sulphated 3 alpha- or beta-hydroxysteroids in serum. The present assay method is highly specific, reliable and reproducible and is thus applicable to a clinical study on the metabolism of sulphated 3 alpha- and beta-hydroxysteroids in patients with adrenal or gonadal diseases.

Neutral steroid metabolites in patients with uraemia and after renal transplantation: a quantitative and qualitative study in body fluids

Steroid metabolites enriched from urine, haemofiltrate, and CAPD-dialysate (Continuous Ambulatory Peritoneal Dialysis) were identified by gas chromatography-mass spectrometry and quantified by capillary gas chromatography. The study included twenty healthy controls, twenty-six non-dialysed uraemics, thirty-nine patients on regular dialysis treatment, and twenty-two allograft recipients. Compared to the 24 h urinary excretion rates of controls the excretion rates of androsterone and etiocholanolone were in the lower normal range up to significantly decreased in the body fluids of all patients, and those of the corticoid metabolites were also significantly decreased. 11-Oxygenated androstanolones in urine from non-dialysed uraemics correlated significantly decreased. 11-oxygenated androstano-levels and were significantly increased, but normal in haemofiltrate and CAPD-dialysate, while in urine of allograft recipients the values were significantly lower.

Constituents of human meconium--I. Identification of 3-hydroxy-etianic acids

The monohydroxylated fraction of bile acids of human meconium was analyzed by capillary GC-MS. In the sulfate-glucuronide fraction three saturated, and one unsaturated C20 steroidal acids were found. These acids were identified as 3 alpha-hydroxy-5 alpha-, 3 alpha-hydroxy-5 beta-,3 beta-hydroxy-5 alpha-androstane-17 beta-carboxylic, and 3 beta-hydroxyandrost-5-ene-17 beta-carboxylic based on the unequivocal GC-MS comparison with standards of all possible epimers at C-3, 5 and 17. The amount of the major C20 acid, 3 alpha-hydroxy-5 alpha-androstane-17 beta-carboxylic, in meconium was 0.2 nmol/g, i.e. 5 to 10 times the amount of lithocholic acid. To prevent the oxidation of 21-hydroxy-20-oxopregnanes to C20 acids meconium was extracted in the presence of sodium borohydride. In the absence of this reducing agent the amount of 3 beta-hydroxyandrost-5-ene-17 beta-carboxylic acid was increased and its 17 alpha-epimer could be detected. This indicates partial artifactual formation of this C20 acid from 21-hydroxypregnenolone, which is known to be present in human meconium. The amount of the saturated C20 acids was unaffected by the presence of sodium borohydride in the extraction medium, and their native occurence in human meconium was further confirmed by the absence of their 17 alpha-epimers in extracts obtained both with and without borohydride. The probable metabolic origin of C20 acids in the fetal-placental-maternal unit is discussed.

Quantitative analysis of steroid profiles from urine by capillary gas chromatography. I. Accuracy and reproducibility of the sample preparation

A method is described for the determination of steroid profiles from urine by means of gas chromatography using high-efficiency glass capillary columns. The accuracy and reproducibility of essential steps in the sample preparation (extraction of steroids and steroid conjugates by means of XAD-2, enzymatic hydrolysis with Helix pomatia juice, solvolysis in acidified ethyl acetate and alkali wash) are established using different endogenously labelled urine samples, obtained from normal subjects to whom labelled steroids had been administered. Preliminary results are given on the reproducibility of the derivatization procedure (formation of methoxime-trimethylsilyl (MO-TMS) ethers), the gas chromatographic analysis and the whole method. Two procedures for the purification of MO-TMS steroid derivatives are compared. Application of the method to urine samples of patients with various endocrine disorders is included.

Automated urinary steroid profiles by capillary column gas-liquid chromatography and a computing integrator

13 Urinary steroid metabolites have been determined by automated gas-liquid chromatography with a 20-m glass capillary column and a computing integrator. Concentrations up to 2 mg/24 h computed by the integrator compare well with those obtained by peak height measurements. At higher concentrations discrepancies occurred, paticularly for the C21 steroids where falsely low values were calculated using peak heights. Mean excretion by healthy males and females of seven steroid metabolities is presented.