A fluorometric assay using 4-methylumbelliferyl α-l-iduronide for the estimation of α-l-iduronidase activity and the detection of Hurler and Scheie syndromes

Hopwood, John J.; Muller, Vivienne; Smithson, Alan; Baggett, N.

doi:10.1016/0009-8981(79)90121-9

Cited by 130 publications

(66 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…H2O content of cecal samples was determined by weighing samples before and after they were desiccated under vacuum for 30 hours at 25°C. Kidney and liver IDUA activity was measured using a fluorometric assay (34).…”

Section: Figurementioning

confidence: 99%

Urolithiasis and hepatotoxicity are linked to the anion transporter Sat1 in mice

Dawson

Russell²,

Lee³

et al. 2010

J. Clin. Invest.

101

127

View full text Add to dashboard Cite

Urolithiasis, a condition in which stones are present in the urinary system, including the kidneys and bladder, is a poorly understood yet common disorder worldwide that leads to significant health care costs, morbidity, and work loss. Acetaminophen-induced liver damage is a major cause of death in patients with acute liver failure. Kidney and urinary stones and liver toxicity are disturbances linked to alterations in oxalate and sulfate homeostasis, respectively. The sulfate anion transporter-1 (Sat1; also known as Slc26a1) mediates epithelial transport of oxalate and sulfate, and its localization in the kidney, liver, and intestine suggests that it may play a role in oxalate and sulfate homeostasis. To determine the physiological roles of Sat1, we created Sat1 -/-mice by gene disruption. These mice exhibited hyperoxaluria with hyperoxalemia, nephrocalcinosis, and calcium oxalate stones in their renal tubules and bladder. Sat1 -/-mice also displayed hypersulfaturia, hyposulfatemia, and enhanced acetaminophen-induced liver toxicity. These data suggest that Sat1 regulates both oxalate and sulfate homeostasis and may be critical to the development of calcium oxalate urolithiasis and hepatotoxicity.

show abstract

Section: Figurementioning

confidence: 99%

Urolithiasis and hepatotoxicity are linked to the anion transporter Sat1 in mice

Dawson

Russell²,

Lee³

et al. 2010

J. Clin. Invest.

101

127

View full text Add to dashboard Cite

show abstract

“…This substrate is known to be contaminated with 4-methylumbelliferyl &B-D-glucuronide [ 141. As cy-L-iduronidase has negligible activity at pH 2.8 [14] it was possible to measure the amount of contaminating ,&D-glucuronide by comparing the rates of hydrolysis by the liver extract at pH 2.8 of 0.5 mM 4-methylumbelliferyl a-L-iduronide with a series of known concentrations of rl-methylumbelliferyl-B-D-glucuronide.…”

Section: Glycosidase Assaysmentioning

confidence: 99%

Specific inhibition of human β‐D‐glucuronidase and α‐L‐iduronidase by a trihydroxy pipecolic acid of plant origin

et al. 1984

View full text Add to dashboard Cite

The glucuronic acid analogue of 1‐deoxynojirimycin, 2(S)‐carboxy‐3(R), 4(R), 5(S)‐trihydroxypiperidine, recently isolated from seeds of Baphia racemosa, is a novel specific inhibitor of human liver β‐D‐glucuronidase and α‐L‐iduronidase. No other glycosidases are inhibited. The inhibition of β‐D‐glucuronidase is competitive, with a K i of 8 × 10−5 M and is pH‐dependent. This inhibitor may be useful to induce a mucopolysaccharidosis or to investigate the function of microsomal β‐D‐glucoronidase.

show abstract

“…Characterization of the physicokinetic properties of the defective enzymes in fibroblast and leukocyte extracts has been difficult due to the low levels of residual activity; estimates have ranged from nondetectable to -1% of normal levels depending on the substrate and assay conditions used (7)(8)(9)(10). However, Hopwood and Muller (7) reported that the apparent Km values of the residual activity in MPS IH fibroblast extracts were elevated 4-to 10-fold toward a radiolabeled disaccharide substrate derived from heparan sulfate, whereas the apparent Km value for the MPS IS and MPS IH-S residual activities were in the normal range.…”

Section: Introductionmentioning

confidence: 99%

Mucopolysaccharidosis type I subtypes. Presence of immunologically cross-reactive material and in vitro enhancement of the residual alpha-L-iduronidase activities.

Schuchman

Desnick²

1988

J. Clin. Invest.

View full text Add to dashboard Cite

The enzymatic and immunologic properties of the defective residual a-L-iduronidase activities were investigated in fibroblast extracts from the three subtypes of mucopolysaccharidosis type I, Hurler (MPS IH), Scheie (MPS IS), and HurlerScheie (MPS IH-S) diseases. Using 4-methylumbelliferyl-a-L-iduronide (4MU-a-Id), the activities in fibroblast extracts from all three subtypes were less than 0.1% of normal. Rocket immunoelectrophoresis with monospecific rabbit anti-human a-L-iduronidase polyclonal antibodies, as well as immunoblots using a monoclonal antibody, revealed the presence of crossreactive immunologic material (CRIM) in extracts prepared from each subtype. When the samples were equalized for 8-hexosaminidase A activity, 38-105% of normal enzyme protein was detected. The sequential addition of cystamine, MgCl2 and pyridoxal phosphate increased the residual 4MU-a-Id activities in subtype extracts up to about 35% of normal mean fibroblast activity. Cystamine, MgC2 or pyridoxal phosphate alone enhanced the residual activities two-to fourfold, whereas the sequential addition of all three compounds was required for maximal effect. Of the six B6 vitamers evaluated, only the negatively charged forms, pyridoxamine (PLN), pyridoxamine phosphate (PNP), and pyridoxal phosphate (PLP), stimulated the residual activities. The addition of dermatan sulfate or heparan sulfate to the subtype extracts, followed by treatment with the effector compounds, similarly inhibited both the normal and enhanced MPS I activities. Heat inactivation experiments confirmed the fact that the mutant iduronidase activity was reconstituted and that the observed increase in enzymatic activity was not an artifact of the fluorogenic assay. These results suggest that the presence of certain thiol reducing agents, divalent cations and negatively charged B6 vitamers can alter the conformation of the mutant ac-L-iduronidase in vitro such that the hydrolysis of 4MU-a-Id is enhanced into the heterozygote range.

show abstract

A fluorometric assay using 4-methylumbelliferyl α-l-iduronide for the estimation of α-l-iduronidase activity and the detection of Hurler and Scheie syndromes

Cited by 130 publications

References 13 publications

Urolithiasis and hepatotoxicity are linked to the anion transporter Sat1 in mice

Urolithiasis and hepatotoxicity are linked to the anion transporter Sat1 in mice

Specific inhibition of human β‐D‐glucuronidase and α‐L‐iduronidase by a trihydroxy pipecolic acid of plant origin

Mucopolysaccharidosis type I subtypes. Presence of immunologically cross-reactive material and in vitro enhancement of the residual alpha-L-iduronidase activities.

Contact Info

Product

Resources

About