Proteolytic Activity of Skeletal Muscle of Normal and Dystrophic Chickens and Rabbits

Aa, Iodice; Leong,; Im, Weinstock

doi:10.1159/000457862

Cited by 16 publications

(3 citation statements)

References 9 publications

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“…This appears to relate to slowing down of the growth of the muscle and actual atrophy. This would seem to agree with the in vitro data of Iodice, Leong and Weinstock (14) which showed that the rate of autolysis of muscle extracts could be increased by adding purified muscle cathepsin D. What is here represented as cathepsin D may actually be the combined activities of cathepsin A and D since while purified cathepsin A does not attack hemoglobin it can apparently attack breakdown produlcts of hemoglobin ( 2 2 ) . The increased levels of activities of cathepsins A and D observed in dystrophic muscles are probably due to increased levels of enzyme since the properties of these enzymes isolated from normal muscle appear to be identical with those isolated from dystrophic muscle (22).…”

supporting

confidence: 87%

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Proteolytic Activity During Growth of Hypertrophic and Atrophic Muscles of Genetically Dystrophic Chickens

Peterson¹,

Lilyblade²,

Bond³

1972

Experimental Biology and Medicine

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supporting

confidence: 87%

“…A suggestion as to the effect of relative level of proteolytic activity is seen in the experiments of Iodice, Leong and Weinstock (14) in which the rate of autolysis of chicken muscle extracts was increased by addition of purilfied cathepsin D. The specific substrate (s) for this enzyme is unknown.…”

mentioning

confidence: 99%

Proteolytic Activity During Growth of Hypertrophic and Atrophic Muscles of Genetically Dystrophic Chickens

Peterson¹,

Lilyblade²,

Bond³

1972

Experimental Biology and Medicine

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“…However, Dr. Iodice has isolated the "hemoglobin splitting" activity of muscle and obtained a highly purified cathepsin D-like enzyme,47 that, when added to muscle extracts, increased autolysis severalfold. 43 Cathepsin is, therefore, probably involved in autolysis, although it is not necessarily the rate-controlling step in the overall pathway.…”

Section: Airtolysis and Cathepsin Activitymentioning

confidence: 99%

Comparative Biochemistry of Myopathies*

Weinstock

1966

Annals of the New York Academy of Sciences

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Research programs, in our laboratory and others, are designed to obtain a better understanding of the biochemical changes that occur in muscle-wasting conditions, and ultimately to determine the primary lesion( s) that initiates the wasting process. Interpretation of experimental findings in these investigations are complicated by such factors as infiltration of dystrophic muscle by other tissue elements, and by lack of an absolute baseline to which to refer any observed changes, i.e., wet weight, protein, DNA, whole muscle, etc., all of which involve some limitation as a reference base. Evaluation of the relative importance of similarities vs. differences in the biochemistry of different types of muscle-wasting conditions and in different species presents an additional complication. Many of the changes observed in dystrophic muscle are undoubtedly of a secondary nature, and our present knowledge does not yet obviously indicate a direct experimental approach to the determination of the primary lesion.Since first observing the increased cathepsin activity (against a hemoglobin substrate) in muscle of rabbits with nutritional muscular dystrophy resulting from vitamin E deficiency' and in muscle of mice with a hereditary muscular dystrophy2, we have been interested in the enzymatic mechanism that may be responsible for the loss of muscle constituents in myopathic conditions. DeDuve and co-workers 3-5 have demonstrated that there is a group of hydrolytic enzymes, with optimum activity in the acid pH range, that are segregated in intracellular particles called lysosomes. It was proposed that these lysosomal acid hydrolases are the primary catabolic mechanism of the cell and are activated by various pathological conditions which cause rupture of the lysosomal membrane.5 Investigations of such acid hydrolases in nutritional and hereditary muscular dystrophy by Tappel, Zalkin, and coworker^^^^ revealed that hydrolase activities were markedly increased and indicated the lysosomal character of these enzymes. These investigators suggested that some pathological trigger mechanism caused the rupture of the lysosomal membrane and thus permitted the initiation of cellular necrosis; however, most of the large increments in hydrolase activities were attributed to invading macrophage cells and were therefore considered to be a secondary phenomenon. However, in denervation atrophy, in which there is no appreciable infiltration,8,9 it has been reported that total activity (activity in an entire muscle or muscle group) of cathespinlo and P-glucuronidasel' is increased. Similarly, total activity of cathepsin was found to be increased in nutritional muscular dystrophy.12 Vitamin E Deficiency and Denervation AtrophyTo determine the extent that invading inflammatory cells contribute to the increased acid hydrolase activity of dystrophic muscle, and to establish whether the loss of muscle substance in dystrophy and in denervation atrophy is due to a common enzymatic mechanism, we have investigated the separate and concurrent effects of nu...

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Increase in the amount of elongation factor 2 in chicken muscular dystrophy

1984

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The amount of elongation factor 2 (EF2) in the cytoplasm and ribosome of breast muscle cell from normal and dystrophic strains of chicken was measured. Concentration in the cytoplasm of 20-day-old embryonic dystrophic muscle was higher than that in normal muscle, but no difference in content was found in muscles of 15-day-old embryos. The amount of EF2 bound to ribosomes was identical in normal and dystrophic muscles during all stages of development. Peptide mapping patterns of partial proteolytic fragments of EF2 from normal and dystrophic chicken breast muscles were similar. The increase in cytoplasmic protein synthetic activity of dystrophic breast muscles reported previously seems to be due to the corresponding increase in the number of EF2 molecules rather than to their modification in dystrophic muscle.

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Proteolytic Activity of Skeletal Muscle of Normal and Dystrophic Chickens and Rabbits

Cited by 16 publications

References 9 publications

Proteolytic Activity During Growth of Hypertrophic and Atrophic Muscles of Genetically Dystrophic Chickens

Proteolytic Activity During Growth of Hypertrophic and Atrophic Muscles of Genetically Dystrophic Chickens

Comparative Biochemistry of Myopathies*

Increase in the amount of elongation factor 2 in chicken muscular dystrophy

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