Biochemistry of the developing rat brain V. cell-free incorporation of L-[i-14C]leucine into microsomal protein

Murthy, M.R.V.; Rappoport, D.A.

doi:10.1016/0005-2787(65)90217-0

Cited by 81 publications

(16 citation statements)

References 13 publications

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“…They found that each tissue has a distinct pattern of incorporation of [14C]leucine into protein as a function of age. The decrease with age in protein synthesis of rat (Breuer & Florini, 1965) and mouse (Srivastava, 1969) skeletal muscle, of rat brain (Murthy & Rappoport, 1965;Ekstrom, Liu & Richardson, 1980), and the increase in rat liver (Murthy, 1966) in in vitro systems agree with the in vivo results of Kanungo et al (1970). In contrast, Mainwaring (1969) observed a decline in the in vitro incorporation of [Wlphenylalanine into the liver of old mice, and a decline in the in vivo rate of liver protein synthesis has been observed in old Sprague-Dawley rats .…”

Section: Rationale For the Study Of Protein Metabolism During Agingsupporting

confidence: 74%

“…These results are in contradiction to a large body of literature indicating a decline in brain protein synthesis after birth. Such age-related decreases have been observed in rats (Murthy & Rappoport, 1965;Yamagami, Fritz & Rappoport, 1966;Andrews & Tata, 1971 ;Barra et al, 1973;Dunlop, Van Elden & Lajtha, 1977b), and mice (Johnson & Belytschko, 1969;Lerner & Johnson, 1970, 1971. The decreases in brain protein synthesis were reported to occur primarily during the first 3 0 days after birth (Lerner & Johnson, 1970, 1971Andrews & Tata, 1971).…”

Section: Rationale For the Study Of Protein Metabolism During Agingmentioning

confidence: 91%

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Protein Synthesis and Degradation During Aging and Senescence

Makrides

1983

Biological Reviews

171

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Summary 1. The published results on protein synthesis during aging are contradictory. Possible sources of error and variability include: an insufficient number of different animal ages used; use of whole organs that are cytologically highly heterogeneous; different animal strains; neglecting to measure the specific activity of the precursor pool for protein synthesis; and inadequate methodology for measurement of in vivo rates of protein synthesis. 2. In general, protein synthesis rates in mammals have been reported to decline 4–70% with age. In insects and other organisms, greater losses (60–90%) have been observed. 3. Limited evidence indicates that in some systems a decline in the rate of protein synthesis may be due to alterations (as yet of unknown nature) in the initiation components of the protein synthetic apparatus. Futhermore, some studies suggest that in some organisms aging affects the expression of specific parts of the genome. 4. The significance of results on protein metabolism obtained from some studies with nematodes is at present unknown, owing to problems associated with age‐synchronization methods. Also, the in vitro fibroblast system for the study of human cellular aging has not been met with universal acceptance; it is generally believed that this system has not yet been established as a valid analogy to mammalian aging in vivo. 5. Failure to detect defective enzymes in many old organisms indicates at least that not all proteins are altered during aging. The complete thermal stability of purified enzymes from old organisms suggests that the observed thermolability of the same enzymes in crude cell extracts is not an intrinsic property of those enzymes. Post‐translational modifications (partial denaturation) may constitute the primary mechanism for the production of altered cell polypeptides during aging. 6. The available evidence does not support the concept of an age‐dependent decline in translational accuracy. The future purification to absolute homogeneity of an altered enzyme and its ‘young’ (unaltered) counterpart, and their sequencing, should resolve the question of translational errors. 7. Some degree of age‐related ribosome loss appears to occur in fixed postmitotic cells. In general, the published polyribosomal profiles may represent artefacts due to insufficiently suppressed ribonuclease activity during extraction. 8. The published studies on protein degradation during aging are also contradictory. Some investigators have neglected the possibility of reutilization of labelled amino acid. It is possible that some of the observed age‐related alterations in protein degradation rates are due to altered endocrine status of the animals used, rather than to defects in the protein degradative pathways. The studies utilizing cell culture systems are also contradictory, probably due to different experimental designs. 9. Limited evidence suggests that protein degradation may slow down with age in mammals and nematodes. An inefficient protein degradation system in old organisms could provide a...

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Section: Rationale For the Study Of Protein Metabolism During Agingsupporting

confidence: 74%

Section: Rationale For the Study Of Protein Metabolism During Agingmentioning

confidence: 91%

Protein Synthesis and Degradation During Aging and Senescence

Makrides

1983

Biological Reviews

171

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“…A decrease in brain protein synthesis during development has been well established and has been observed in rats (1,5,21,24), mice (12,13) and chickens (25). The decrease in brain protein synthesis during development has been shown to occur primarily during the first 30 days after birth (5,12,16,21,25); however, brain protein synthesis appears to decrease further after 30 days of age (5,25).…”

mentioning

confidence: 99%

“…The decrease in brain protein synthesis during development has been shown to occur primarily during the first 30 days after birth (5,12,16,21,25); however, brain protein synthesis appears to decrease further after 30 days of age (5,25).…”

mentioning

confidence: 99%

Changes in Brain Protein Synthesis during the Life Span of Male Fischer Rats

Ekstrom

Liu

Richardson³

1980

Gerontology

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The cell-free protein synthetic activity of the postmitochondrial supernatant isolated from whole brain of 6- to 32-month-old male Fischer F344 rats was compared. Protein synthesis decreased 56% from 6 to 32 months of age. The decrease in cell-free protein synthesis was not due to an age-related increase in RNase activity. Although monomeric ribosomes (ribosomes stripped of mRNA) isolated from the brains of older rats were less active in polyuridylic acid directed polyphenylalanine synthesis, the fidelity of polyuridylic acid translation by monomeric ribosomes did not decrease with increasing age.

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“…It has been demonstrated that the overall activity of the p H 5 enzyme fractions containing mainly t R N A a n d aminoacyl-tRNA (AA-tRNA) synthetases does not change with age (Murthy andRappoport, 1965: Johnson andBelytschko, 1969;B. E. Gilbert, 1978), with the exception of some tRNAs (Barra et al, 1972).…”

mentioning

confidence: 99%

Role of Elongation Factor 1 in the Translational Control of Rodent Brain Protein Synthesis

Vargas

Castañeda

1982

Journal of Neurochemistry

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The translational control of protein synthesis during early postnatal neural development and aging was examined in the mouse and the rat. The activity of brain elongation factor 1 (bEF-1) was found to decrease exponentially with age and to decline parallel to the age-dependent decrease in total protein synthesis in both rodents. This decrement in bEF-1 activity fell within the range of reported age-related decreases in protein synthesis in in vitro systems. The factor was present in multiple forms; the lighter species predominated in older animals, whereas the young light form apparently disappeared with increasing age, and was replaced by other arising from the heavy form. Elongation factor 1 derived from young brains functioned as a rate-limiting component in polypeptide synthesis in previously saturated adult systems. The data suggest that bEF-1 has an important modulatory effect on total brain protein synthesis.

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Biochemistry of the developing rat brain V. cell-free incorporation of L-[i-14C]leucine into microsomal protein

Cited by 81 publications

References 13 publications

Protein Synthesis and Degradation During Aging and Senescence

Protein Synthesis and Degradation During Aging and Senescence

Changes in Brain Protein Synthesis during the Life Span of Male Fischer Rats

Role of Elongation Factor 1 in the Translational Control of Rodent Brain Protein Synthesis

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