Biochemical study of sialidosis type I in a Russian family

Tsvetkova, Inna V.; Петушкова, Н. А.; Zolotuchina, T. V.; Kucharenko, V. I.; Rosenfeld, E.L.

doi:10.1007/bf01799483

Cited by 4 publications

(2 citation statements)

References 13 publications

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“…Human leucocytes contain at least two sialidase (neuraminidase) isoenzymes [1,2]. Assays using the synthetic fluorimetric substrate 4-methylumbelliferyl-a-D-N-acetylneuraminic acid (MU-Neu5Ac) detect a freeze-labile activity corresponding to the classic lysosomal enzyme which is absent in certain inherited disorders [3,4]. Although detailed characterization of this lysosomal sialidase in leucocytes was severely limited by its low abundance [5] and membraneor particle-bound nature [6], a soluble analogue with high activity in human placenta has been identified [7].…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the labile activity, low levels of a freeze-stable MU-Neu5Ac sialidase activity have been observed in human leucocytes. Because of its presence in the cells both of healthy subjects and of patients with the inherited disorders sialidosis and galactosialidosis [1,4] it has been regarded as genetically distinct from the labile lysosomal sialidase [1]. The stable isoenzyme has, however, remained poorly understood in terms of its natural substrates, subcellular localization and pathophysiological roles.…”

Section: Introductionmentioning

confidence: 99%

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Freeze-stable sialidase activity in human leucocytes: substrate specificity, inhibitor susceptibility, detergent requirements and subcellular localization

Waters

Corfield

Eisenthal

et al. 1994

Biochemical Journal

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Human leucocytes contain a freeze-stable sialidase (neuraminidase; EC 3.2.1.18) activity in addition to the better-characterized lysosomal freeze-labile enzyme. In order to discriminate between the sialidase activities detected with the synthetic fluorimetric substrate 4-methylumbelliferyl-alpha-D-N-acetylneuraminic acid (MU-Neu5Ac), different tritiated sialoglycoconjugate substrates were prepared. Using this sensitive radioactive assay system, leucocyte sialidase activity towards glycoproteins was shown to be labile to repeated freeze-thawing, but a Triton-stimulated activity towards gangliosides was entirely freeze-stable. Assay conditions were optimized for this freeze-stable ganglioside sialidase activity. Subcellular fractionation of mononuclear leucocytes (MNLs) on Percoll-density gradients showed that this ganglioside sialidase activity was entirely associated with the plasma membrane. Study of the detergent requirements showed that MNLs also demonstrated ganglioside sialidase activity when sodium cholate was present in place of Triton. Cholate-stimulated ganglioside sialidase activity was found to be entirely freeze-stable and localized at the plasma membrane. Studies on whole homogenates of MNLs demonstrated that the Triton-stimulated and cholate-stimulated activities showed similar acidic pH optima at < or = 3.9 and were both strongly inhibited by 2-deoxy-2,3-didehydro-N-acetylneuraminic acid and Cu2+, but not by free N-acetylneuraminic acid, N-(4-nitrophenyl)oxamic acid or heparan sulphate. These results suggest that human MNLs contain, in addition to the lysosomal freeze-labile sialidase, a single sialidase activity which is freeze-stable, ganglioside-specific, plasma membrane-associated and stimulated both by Triton and by cholate.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Freeze-stable sialidase activity in human leucocytes: substrate specificity, inhibitor susceptibility, detergent requirements and subcellular localization

Waters

Corfield

Eisenthal

et al. 1994

Biochemical Journal

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Clinical and genetic characteristics of type I sialidosis patients in mainland China

Zhang

et al. 2020

Ann Clin Transl Neurol

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ObjectiveType I sialidosis (ST‐1) is a rare autosomal recessive inherited disorder. To date, there has been no study on ST‐1 patients in mainland China.MethodsWe reported in detail the cases of five Chinese ST‐1 patients from two centers, and summarized all worldwide cases. Then, we compared the differences between Chinese and foreign patients.ResultsA total of 77 genetically confirmed ST‐1 patients were identified: 12 from mainland China, 23 from Taiwan, 10 from other Asian regions, and 32 from European and American regions. The mean age of onset was 16.0 ± 6.7 years; the most common symptoms were myoclonus seizures (96.0%), followed by ataxia (94.3%), and blurred vision (67.2%). Compared to other groups, the onset age of patients from mainland China was much younger (10.8 ± 2.7 years). The incidence of visual impairment was lower in patients from other Asian regions than in patients from mainland China and Taiwan (28.6% vs. 81.8%–100%). Cherry‐red spots were less frequent in the Taiwanese patients than in patients from other regions (27.3% vs. 55.2%–90.0%). Furthermore, 48 different mutation types were identified. Chinese mainland and Taiwanese patients were more likely to carry the c.544A > G mutation (75% and 100%, respectively) than the patients from other regions (only 0%–10.0%). Approximately 50% of Chinese mainland patients carried the c.239C > T mutation, a much higher proportion than that found in the other populations. In addition, although the brain MRI of most patients was normal, 18F‐FDG‐PET analysis could reveal cerebellar and occipital lobe hypometabolism.InterpretationST‐1 patients in different regions are likely to have different mutation types; environmental factors may influence clinical manifestations. Larger studies enrolling more patients are required.

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