Incorporation of C14-amino acids into protein of isolated diaphragms: effect of epinephrine and norepinephrine

1960 ◽  
Vol 198 (1) ◽  
pp. 54-56 ◽  
Author(s):  
Ira G. Wool

When diaphragms isolated from normal rats were incubated with a C14-amino acid the addition of epinephrine or norepinephrine decreased incorporation of C14 into muscle protein. The inhibition occurred whether epinephrine was added in vitro or administered in vivo. The minimal effective concentration of epinephrine in vitro was 0.1 µg/ml. When the glucose concentration in the medium was raised to 300 mg % or more the epinephrine induced inhibition of amino acid incorporation into muscle protein was no longer observed.

1973 ◽  
Vol 51 (12) ◽  
pp. 933-941 ◽  
Author(s):  
Njanoor Narayanan ◽  
Jacob Eapen

The effect of cycloheximide in vitro and in vivo on the incorporation of labelled amino acids into protein by muscles, liver, kidneys, and brain of rats and pigeons was studied. In vitro incorporation of amino acids into protein by muscle microsomes, myofibrils, and myofibrillar ribosomes was not affected by cycloheximide. In contrast, administration of the antibiotic into intact animals at a concentration of 1 mg/kg body weight resulted in considerable inhibition of amino acid incorporation into protein by muscles, liver, kidneys, and brain. This inhibition was observed in all the subcellular fractions of these tissues during a period of 10–40 min after the administration of the precursor. Tissue homogenates derived from in vivo cycloheximide-treated animals did not show significant alteration in in vitro amino acid incorporation with the exception of brain, which showed a small but significant enhancement.


2019 ◽  
Author(s):  
Fred R. Ward ◽  
Zoe L. Watson ◽  
Omer Ad ◽  
Alanna Schepartz ◽  
Jamie H. D. Cate

AbstractRibosome engineering has emerged as a promising field in synthetic biology, particularly concerning the production of new sequence-defined polymers. Mutant ribosomes have been developed that improve the incorporation of several non-standard monomers including D-amino acids, dipeptides, and β-amino acids into polypeptide chains. However, there remains little mechanistic understanding of how these ribosomes catalyze incorporation of these new substrates. Here we probed the properties of a mutant ribosome–P7A7–evolved for better in vivo β-amino acid incorporation through in vitro biochemistry and cryo-electron microscopy. Although P7A7 is a functional ribosome in vivo, it is inactive in vitro, and assembles poorly into 70S complexes. Structural characterization revealed large regions of disorder in the peptidyltransferase center and nearby features, suggesting a defect in assembly. Comparison of RNA helix and ribosomal protein occupancy with other assembly intermediates revealed that P7A7 is stalled at a late stage in ribosome assembly, explaining its weak activity. These results highlight the importance of ensuring efficient ribosome assembly during ribosome engineering towards new catalytic abilities.


1959 ◽  
Vol 197 (5) ◽  
pp. 1089-1092 ◽  
Author(s):  
Ira G. Wool ◽  
Edward I. Weinshelbaum

The incorporation of C14-amino acids into a protein fraction of diaphragms incubated in vitro was measured. Adrenalectomy led to an increase in amino acid incorporation into protein. Cortisone (0.3 mg/day) administered to adrenalectomized rats tended to restore incorporation to normal; desoxycorticosterone (0.06 mg/day) was without effect. Larger doses of cortisone (1 or 2 mg/day) produced a marked reduction in amino acid incorporation into diaphragms from both normal and adrenalectomized rats. Fasting reduced histidine incorporation into muscle protein whether the donor rat was normal or adrenalectomized. Phenylalanine-3-C14 incorporation into diaphragm protein was measured at several phenylalanine concentrations. Despite large (100-fold) changes in the phenylalanine pool size the percentage increase in C14 incorporation after adrenalectomy was similar.


1955 ◽  
Vol 215 (1) ◽  
pp. 111-124 ◽  
Author(s):  
Henry Borsook ◽  
Adolph Abrams ◽  
Peter H. Lowy

1984 ◽  
Vol 247 (5) ◽  
pp. E639-E644
Author(s):  
C. M. Cameron ◽  
J. L. Kostyo ◽  
J. A. Rillema ◽  
S. E. Gennick

The biological activity profile of reduced and S-carboxymethylated human growth hormone (RCM-hGH) was determined to establish its suitability for study of the diabetogenic property of hGH. RCM-hGH was found to have greatly attenuated in vivo growth-promoting activity in the 9-day weight-gain test in hypophysectomized rats (approximately 1%) and to have a similar low order of in vitro activity in stimulating amino acid incorporation into the protein of the isolated rat diaphragm. RCM-hGH also only had approximately 1% of the in vitro insulin-like activity of the native hormone on isolated adipose tissue from hypophysectomized rats. In contrast, RCM-hGH retained substantial in vivo diabetogenic activity in the ob/ob mouse, appearing to have approximately 50% of the activity of the native hormone. RCM-hGH was also found to retain significant, although attenuated (25%), in vitro lactogenic activity when tested for the ability to stimulate amino acid incorporation into a casein-rich protein fraction in mouse mammary gland explants. Because RCM-hGH exhibits a high degree of diabetogenic activity, although lacking significant anabolic or insulin-like activities, it will be useful as a "monovalent" probe for the study of the molecular mechanism of the diabetogenic action of GH.


1976 ◽  
Vol 35 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Turner ◽  
P. J. Reeds ◽  
K. A. Munday

1. Net amino acid uptake, and incorporation into protein have been measured in vitro in the presence and absence of porcine growth hormone (GH) in muscle from intact rabbits fed for 5 d on low-protein (LP), protein-free (PF) or control diets.2. In muscle from control and LP animals GH had no effect on the net amino acid uptake but stimulated amino acid incorporation into protein, although this response was less in LP animals than in control animals.3. In muscle from PF animals, GH stimulated both amino acid incorporation into protein and the net amino acid uptake, a type of response which also occurs in hypophysectomized animals. The magnitude of the effect of GH on the incorporation of amino acids into protein was reduced in muscle from PF animals.4. The effect of GH on the net amino acid uptake in PF animals was completely blocked by cycloheximide; the uptake effect of GH in these animals was dependent therefore on de novo protein synthesis.5. It is proposed that in the adult the role of growth hormone in protein metabolism is to sustain cellular protein synthesis when there is a decrease in the level of substrate amino acids, similar to that which occurs during a short-term fast or when the dietary protein intake is inadequate.


1974 ◽  
Vol 140 (3) ◽  
pp. 549-556 ◽  
Author(s):  
R. L. Boeckx ◽  
K. Dakshinamurti

The effect of administration of biotin to biotin-deficient rats on protein biosynthesis was studied. Biotin treatment resulted in stimulation by more than twofold of amino acid incorporation into protein, both in vivo and in vitro in rat liver, pancreas, intestinal mucosa and skin. Analysis of the products of amino acid incorporation into liver proteins in vivo and in vitro indicated that the synthesis of some proteins was stimulated more than twofold, but others were not stimulated at all. This indicates a specificity in the stimulation of protein synthesis mediated by biotin.


1973 ◽  
Vol 72 (4) ◽  
pp. 684-696 ◽  
Author(s):  
Amirav Gordon ◽  
Martin I. Surks ◽  
Jack H. Oppenheimer

ABSTRACT The in vivo and in vitro stimulation of rat hepatic mitochondrial protein synthesis by thyroxine (T4) was compared. In confirmation of Buchanan & Tapley (1966). T4 added to isolated mitochondria rapidly stimulated [14C] leucine incorporation into mitochondrial protein. The in vitro stimulation was reversed after T4 was removed by incubating the mitochondria with bovine serum albumin (BSA). The decrease in T4 stimulation of protein synthesis appeared proportional to the T4 removed by BSA. Thus, it appears probable that exchangeable T4 controls the in vitro system. In contrast, the increase in mitochondrial protein synthesis which was observed 3 to 4 days after pretreatment of hypothyroid rats with labelled and non-radioactive T4 was not reversed by BSA treatment. Moreover, mitochondrial radioactivity could not be extracted with albumin. The in vivo phenomenon does not, therefore, appear to be related to exchangeable hormone in the mitochondria. Furthermore, the estimated quantity of T4 associated with mitochondria after in vivo stimulation was at least two orders of magnitude less than that required to produce comparable stimulation of mitochondrial protein synthesis in vitro. These findings strongly suggest that in vitro and in vivo stimulation of amino acid incorporation by T4 may be mediated by different biochemical mechanisms.


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