Cathepsin Activity in Normal and Dystrophic Human Muscle

Rj, Pennington; Je, Robinson

doi:10.1159/000458253

Cited by 53 publications

(13 citation statements)

References 12 publications

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“…Some of these results are in accord with those reported by Pennington and Robinson [15]. In contrast to their findings that myoglobin is a better substrate than hemoglobin for acid cathepsin of human muscle, we have found that both myoglobin and hemoglobin are almost equally active as substrates not only for acid cathepsin, but also for neutral and alkaline cathepsins.…”

Section: Discussionsupporting

confidence: 92%

“…The proteins were denatured as described by Pennington and Robinson [15]. Each protein was dialyzed overnight at 5°C against 0.05 mol/1 KC1 to remove excess acid soluble ninhydrin-reacting material.…”

Section: Methodsmentioning

confidence: 99%

“…Human muscle was found to have cathepsin activity against myoglobin substrate over a wide pH range, with peaks at 3.9 and 6.6. Increased activity of acid, neutral and alkaline cathepsins was noted in muscle from patients with Duchenne muscular dystrophy [15]. An increased alkaline cathepsin also occurred in mouse dystrophic muscle [14].…”

Section: Introductionmentioning

confidence: 93%

“…of 0.05 mol/1 NaOH and kept at room temperature for 18 h as described by Pennington and Robinson [15]. The sample was centrifuged and an aliquot of the supernatant was analyzed for protein by the method of Lowry et al [9].…”

Section: Determination Of Non-collagen Protein (Ncp)mentioning

confidence: 99%

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Acid, Neutral and Alkaline Cathepsins in Normal and Diseased Human Muscle

Nc¹,

Cm²

1972

Enzyme

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Homogenates of human skeletal muscle showed autolytic and cathepsin activity over a wide pH range with peaks at 3.6, 6.6 and 8.6. Some evidence was presented for the enzymatic and proteolytic nature of the autolytic process. Both myoglobin and hemoglobin were equally active as substrates at all pH peaks. In mildly abnormal muscle of patients with Duchenne muscular dystrophy, other dystrophies, dermatomyositis and neurogenic atrophies, both autolytic and cathepsin activity in the acid, neutral and alkaline range were either normal or slightly above normal. On the other hand, in severely degenerated muscles of patients with the same disease conditions, large increases in autolytic and cathepsin activity at all pH peaks were found. The increased activity of cathepsins was found to correlate with the degree of muscle degeneration. These results suggest that the cathepsins are involved in the muscle wasting process in human muscle diseases.

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Section: Discussionsupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

Section: Determination Of Non-collagen Protein (Ncp)mentioning

confidence: 99%

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Acid, Neutral and Alkaline Cathepsins in Normal and Diseased Human Muscle

Nc¹,

Cm²

1972

Enzyme

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“…Myoglobin [94], casein [95][96][97] and albumin [98,99], both labeled and non-labeled with chromofore, fluorophor and radioelement are less frequently used to determine cathepsin D.…”

Section: Native Denaturated and Labeled Proteinsmentioning

confidence: 99%

Quantitative determination and localization of cathepsin D and its inhibitors.

Minarowska

Karwowska²,

Gacko³

2009

Folia Histochem Cytobiol.

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Cathepsin D (EC 3.4.23.5) is a lysosomal aspartyl endopeptidase, localized in all cells and tissues, except for mature erythrocytes [1][2][3]. Methods used to determine the activity, concentration and cellular distribution of cathepsin D, but not its inhibitors, have previously been the subject of literature reports [4][5][6][7][8][9][10][11][12]. However, since the time of their publication a number of new substrates and analytical techniques have been implemented. Structure, specificity, mechanism of actionCathepsin D is synthesized in the rough endoplasmic reticulum as preprocathepsin D, built up of 412 amino acid residues [13][14][15]. As a result of cleavage of the 20-amino acid signal prepeptide, it is converted into procathepsin D which undergoes glycosylation and disulphide bridges are formed in its molecule. Procathepsin D is transported from cisterns of the rough endoplasmic reticulum to the Golgi apparatus, from which, with the involvement of mannoso-6-phosphate (M-P-6) receptors, it is transferred to primary lysosomes [16,17]. As the M-6-P receptors are known to occur in the primary lysosomes but not in the mature ones, they can be used to distinguish between these two types of lysosomes [18]. In the acidic environment of the lysosomes (pH 4.5-5.5), due to autocatalytic cleavage of the 44-amino acid propeptide from the N-terminal molecule, procathepsin D is converted into the active one-chain form. The actions of cysteine proteinase, aminopeptidases and carboxypeptidases lead to the formation of an active two-chain form of cathepsin D (Fig. 1). These chains are bound by hydrophobic bonds. The molecular weight of the ultimate mature form of cathepsin D is 48 (14+34) kDa. The proteolytic activities of the one-chain and two-chain forms are very similar [19,20]. Modification of the polypeptide chain, different oligosaccharide composition types and phosphorylation/dephosphorylation in the amino saccharide residues contribute to marked molecular heterogenicity of cathepsin D and cause differences in isoelectric points of the respective isoenzymes between pH 4.5 -6.5 [21,22].The use of peptides with the known primary structure allows identification of amino acid residues that form peptide bonds cleaved by cathepsin D. For this purpose, synthetic peptides [23] and chains A and B of bovine insulin can be used (Fig. 2). Cathepsin D cleaves the peptide bonds found within the polypeptide chain, formed by carboxyl groups of the hydrophobic amino acid residues: aromatic -trypto-

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Therapeutic Trials in Muscular Dystrophy

Enomoto

Bradley

1977

Arch Neurol

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Cathepsin Activity in Normal and Dystrophic Human Muscle

Cited by 53 publications

References 12 publications

Acid, Neutral and Alkaline Cathepsins in Normal and Diseased Human Muscle

Acid, Neutral and Alkaline Cathepsins in Normal and Diseased Human Muscle

Quantitative determination and localization of cathepsin D and its inhibitors.

Therapeutic Trials in Muscular Dystrophy

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