Enzymatic cleavage of glycopeptides

Makino, Mayumi; Kojima, Tsugio; Yamashina, Ikuo

doi:10.1016/0006-291x(66)90344-5

Cited by 98 publications

(51 citation statements)

References 5 publications

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“…Assay for AGA activity The AGA activity assay based on colorimetric measurement of liberated N-acetylglucosamine from the synthetic substrate 2-acetamido-1-13-(Laspartamido)-1,2-dideoxy-13-D-glucose (AADG) (Makino et al, 1966) was performed from COS cells as previously described (Ikonen et al, 1991c). One unit of enzyme activity was defined as the amount of enzyme cleaving ymol of N-acetylglucosamine-Asn linkages/min.…”

Section: Methodsmentioning

confidence: 99%

Lysosomal aspartylglucosaminidase is processed to the active subunit complex in the endoplasmic reticulum.

et al. 1993

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Aspartylglucosaminidase (AGA) is a lysosomal enzyme, the deficiency of which leads to a human storage disease, aspartylglucosaminuria (AGU). Although numerous mutations have been identified in AGU patients, elucidation of the molecular pathogenesis of the disease has been hampered by the missing information on the cellular events resulting in the maturation and activation of the enzyme. Here we used the expression of in vitro mutagenized constructs of the AGA cDNA to define three specific proteolytic trimming steps resulting in mature AGA. Removal of the signal peptide is immediately followed by proteolytic cleavage of the precursor into two subunits and results in biologically active enzyme already in the endoplasmic reticulum. This early activation has not previously been described for lysosomal enzymes. The subsequent lysosomal trimming does not influence the enzymatic activity of AGA. It consists only of a single proteolytic cleavage which removes 10 amino acids from the C‐terminal end of the larger subunit, in contrast to the multistep lysosomal processing observed in several other hydrolases.

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Section: Methodsmentioning

confidence: 99%

Lysosomal aspartylglucosaminidase is processed to the active subunit complex in the endoplasmic reticulum.

et al. 1993

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“…AADGase assay was originally described by Makino and coworkers (14). and a detailed account of our assay system has been reported ( I ) .…”

Section: E N L Y M E Assaysmentioning

confidence: 99%

“…Using phenyl-cu-L-iduronide as a substrate, cu-L-iduronidase activity has been demonstrated to be reduced in leukocytes, serum, and cultured skin fibroblasts from obligate neterozygotes for the Hurler and Scheie syndronies (9,14). IIall and Neufcld (9) demonstrated that the cu-L-iduronidase activity of Hurler heterozygous cdtured skin fibroblasts varied from 20 t o 95% of normal, with a mean value of 46%.…”

Section: Speculationmentioning

confidence: 99%

“…The assay was used for ized by deficient activity of the lysosomal enLyme (ec. 3.2.1.76) controlled studies of families in which the Hurler syndrome has a-L-iduronidase (2,9,14,16). This enzymatic defect results in occurred and appears to be sufficiently accurate and precise to generalized lysosomal accumulation and excessive urinary excre-enable the detection of heterozygosity with greater than 95% contion of partially degraded mucopolysaccharides containing fidence.…”

Section: Speculationmentioning

confidence: 99%

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Enzymatic Diagnosis and Carrier Detection of Aspartylglucosaminuria Using Blood Samples

1976

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“…Stirling was the first to discover the presence of such an enzyme in the human liver (20). Chitobiase is active only after the prior action of aspartylglucosaminidase (EC 3.5.1.26) that removes the asparagine residue to which the N-linked glycan was attached (13). In situations where the latter enzyme is deficient, chitobiase finds the reducing end blocked and is thus unable to cleave the chitobiosyl moiety.…”

mentioning

confidence: 99%

Discrimination between chitinase and chitobiase activities in Candida albicans.

Overdijk¹,

Steijn²

1995

J. Gen. Appl. Microbiol.

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Measurement of chitinase activity in crude homogenates of Candida albicans with the artificial substrates 4-methylumbelliferyl /3-D-N,N',N"-triacetylchitotrioside and 4-methylumbelliferyl/3-D-N,N'-diacetylchitobioside (MU-[G1cNAc]3,2) showed that both chitobiase and chitinase were involved in the liberation of the fluorophore methylumbelliferone (MU). The substrate MU-[G1cNAc]3 appeared to be digested by means of two separate mechanisms, resulting in a lag-phase in the time curve of the MU-release, and thus making this release non-linear with time. The first mechanism is the action of an endochitinase that released MU in one step; this reaction could be inhibited by allosamidin. The second probable mechanism involves the digestion of the substrate by the stepwise release of the outer two G1cNAc residues by a chitobiase, followed either by a third chitobiase-catalyzed release of the final G1cNAc or by the action of a,(3-N-acetylhexosaminidase, that is also present in C. albicans. Hydrolysis of the substrate MU-[ G1cNAc ] 2 was not inhibited by allosamidin, suggesting that the two G1cNAc residues in this substrate are probably released in two steps, either by the action of chitobiase alone, or by the successive action of chitobiase (step 1) and /3-N-acetylhexosaminidase (step 2). Our results show that the activities of the individual enzymes involved in chitin degradation cannot be determined on the basis of MU release in unfractionated homogenates of C. albicans.The literature on chitinases has been reviewed recently by Flach et al. (7).

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Enzymatic cleavage of glycopeptides

Cited by 98 publications

References 5 publications

Lysosomal aspartylglucosaminidase is processed to the active subunit complex in the endoplasmic reticulum.

Lysosomal aspartylglucosaminidase is processed to the active subunit complex in the endoplasmic reticulum.

Enzymatic Diagnosis and Carrier Detection of Aspartylglucosaminuria Using Blood Samples

Discrimination between chitinase and chitobiase activities in Candida albicans.

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