Leukocytic enzyme differences between the clinical forms of malnutrition

Avila, JoséLuis; Velazquez-Avila, Gladys; Silva-Correa, Carmen R.; Castillo, Celia; Convit, J

doi:10.1016/0009-8981(73)90336-7

Cited by 20 publications

(7 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1, channels 1-3) in agreement with previous evidence (5)(6)(7)(8)(9)(10)(11)(12). Similar double bands of acidic a-mannosidase have been observed with electrophoresis in the mice (26) and in cattle (31).…”

Section: Discussionsupporting

confidence: 80%

“…A similar inherited mannosidosis has been described in Angus cattle and also results in absence of both acidic a-mannosidase components (31,32). The two purified molecular forms of human MANB show similar kinetic properties, molecular weights, and thermostabilities, and are immunologically identical (8)(9)(10)(11)(12). Since the loss of both forms occurs in mannosidosis and these forms appear to be closely interrelated, this suggests that mannosidosis results from a structural gene defect common to both forms.…”

Section: Discussionmentioning

confidence: 76%

“…The acidic MANB activity (optimum pH 4.0-4.5) consists of two closely related molecular forms which show similar thermostability, enzyme kinetics, and molecular weight, while the single neutral MANA enzyme (optimum pH 6.0-6.5) is thermolabile and enzymatically distinct (8)(9)(10). The two acidic a-mannosidase enzymes are distributed in the lysosome while the neutral form shows highest activity in the cytoplasm (8,9). The two purified acidic, lysosomal forms interconvert spontaneously (9,10) or with neuraminidase treatment (11); they are immunologically identical (12) and appear to be structurally and genetically interrelated.…”

mentioning

confidence: 99%

“…Acidic and neutral forms of amannosidase have been separated by DEAE-cellulose chromatography (5) and cellulose acetate electrophoresis (7). The acidic MANB activity (optimum pH 4.0-4.5) consists of two closely related molecular forms which show similar thermostability, enzyme kinetics, and molecular weight, while the single neutral MANA enzyme (optimum pH 6.0-6.5) is thermolabile and enzymatically distinct (8)(9)(10). The two acidic a-mannosidase enzymes are distributed in the lysosome while the neutral form shows highest activity in the cytoplasm (8,9).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Mannosidosis: assignment of the lysosomal alpha-mannosidase B gene to chromosome 19 in man.

Champion¹,

Shows²

1977

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Human a-mannosidase activity (a-D-mannoside mannohydrolase, EC 3.2.1.24) from tissues and cultured skin fibroblasts was separated by gel electrophoresis into a neutral, cytoplasmic form (a-mannosidase A) and two closely related acidic, lysosomal components (a-mannosidase B). Human mannosidosis, an inherited glycoprotein storage disorder, has been associated with severe deficiency of both lysosomal amannosidase B molecular forms. Chromosome assignment of the gene coding for human a-mannosidase B (MANB) has been determined in human-mouse and human-Chinese hamster somatic cell hybrids. The human a-mannosidase B phenotype showed concordant segregation with the human -enzyme glucosephosphate isomerase (GPI) (D-glucose-6-phosp ate ketolisomerase, EC 5.3

show abstract

Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 76%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Mannosidosis: assignment of the lysosomal alpha-mannosidase B gene to chromosome 19 in man.

Champion¹,

Shows²

1977

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Our results suggest the possibility that the lysosomal glycosaminoglycans function as regulators of the hydrolytic capacity of polymorphonuclear leucocyte lysosomes. A preliminary account of some of this work has been given (Avila & Convit, 1973c). Vol.…”

mentioning

confidence: 99%

Inhibition of leucocytic lysosomal enzymes by glycosaminoglycans in vitro

Avila¹,

Convit²

1975

Biochemical Journal

110

View full text Add to dashboard Cite

1. A lysosomal fraction was separated by density-gradient centrifugation from a highly purified human polymorphonuclear leucocyte suspension. 2. Some 23 different lysosomal enzymes were assayed for activity in the presence of various concentrations of glycosaminoglycans. 3. The 21 acid hydrolases assayed were strongly inhibited to different degrees by low (0-12mmol/l) concentrations of glycosaminoglycans in a pH-dependent manner. Thus inhibitions were stronger below pH4.5, with activity returning to control values at about pH5.0. 4. On a molar basis, the inhibitory activity for the several glycosaminoglycans studied was: heparin>chondroitin sulphate>hyaluronic acid. 5. Once the glycosaminoglycan-acid hydrolase complex was formed, it was partially dissociated by slight elevations in the pH ofthe incubation medium, by increasing the ionic strength of the incubation medium, or by adding several cationic proteins (e.g. histone, protamine). 6. As leucocytic lysosomes contain large amounts of chondroitin sulphate, and have a strongly acid intragranular pH, we suggest that glycosaminoglycans may modify lysosomal function through the formation of complexes with lysosomal enzymes, by inhibiting the digestive activity of the acid hydrolases when the intralysosomal pH is below their pl.

show abstract