title: Protein degradation in skin fibroblasts from patients with Duchenne muscular dystrophy.
abstract: The rates of degradation of [3H]leucine-labelled proteins have been measured in cultures of skin fibroblasts obtained from normal controls (five subjects) and patients with Duchenne muscular dystrophy (six subjects). Cultures were incubated with [3H]leucine (10 microCi/ml) for 60 min to label "short-lived" proteins, and with [3H]leucine (5 microCi/ml) for 60 h to label "long-lived" proteins. Optimal wash procedures were devised for removal of [3H]leucine from the extracellular space and from cell pools before beginning degradation measurements. Re-utilization of [3H]leucine released from degraded labelled proteins was prevented by supplementing the medium with 4mM-leucine. Rates of degradation did not depend on the growth state of the cells or on cell age over the range used (passages eight-20). Degradation of long-lived proteins was approximately linear over a 24h period, at a rate of 1.0% per h. 30% of short-lived protein was degraded within 6h. No differences were observed between protein degradation in normal fibroblasts and in those from patients with Duchenne muscular dystrophy.
mesh_terms: D000293:Adolescent; D000328:Adult; D002453:Cell Cycle; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007223:Infant; D007930:Leucine / Q000378:metabolism; D009136:Muscular Dystrophies / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D012867:Skin / Q000166:cytology / Q000378:metabolism*
chemical_list: D011506:Proteins; D007930:Leucine