Fibre Type-Specific Enzyme Activity Profiles. A Single Fibre Study of the Effects of Chronic Stimulation on the Rabbit Fast-Twitch Tibialis Anterior Muscle

The effect of thyroid status on the expression of cytochrome c oxidase (CYTOX) and the activities of citrate synthase (CS) and phosphofructokinase (PFK) were examined in chronically stimulated (10 Hz; 35 days) and contralateral, nonstimulated rat tibialis anterior muscle of hypothyroid, hyperthyroid, and euthyroid animals. Stimulation increased CYTOX activity by 2.7-, 3.2-, and 4.9-fold in hyperthyroid, euthyroid, and hypothyroid animals, respectively, to similar absolute values. CS displayed similar increases. Stimulation reduced PFK activity in hypothyroid and euthyroid animals to 45% and 60% of control values. This effect was abolished with hyperthyroidism. Thus stimulation and thyroid hormone act antagonistically on PFK activity. Stimulation increased CYTOX subunit III (mitochondrially encoded) mRNA by 2.5- and 2.9-fold in hyperthyroid and euthyroid animals. Similar increases were observed in the nuclear-encoded mRNAs of CYTOX subunit VIc in euthyroid muscle. In hyperthyroid and euthyroid conditions, the mRNA changes paralleled the increases in enzyme activity. In hypothyroid muscle, the increase in mRNA was less for subunit VIc than III, suggesting that hypothyroidism upsets the coordinate expression of nuclear and mitochondrial genes. Further, the increases in CYTOX activity exceeded that of both subunit mRNAs in hypothyroid muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

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Enzyme activities in the tibialis anterior muscle of young moderately active men and women: relationship with body composition, muscle cross-sectional area and fibre type composition

Acta Physiologica Scandinavica ◽

10.1046/j.1365-201x.2002.t01-2-01004.x ◽

2002 ◽

Vol 176 (3) ◽

pp. 215-225 ◽

Cited By ~ 53

Author(s):

Å. Jaworowski ◽

M. M. Porter ◽

A. M. Holmbäck ◽

D. Downham ◽

J. Lexell

Keyword(s):

Body Composition ◽

Fibre Type ◽

Tibialis Anterior ◽

Tibialis Anterior Muscle ◽

Sectional Area ◽

Cross Sectional ◽

Fibre Type Composition ◽

Men And Women ◽

Type Composition ◽

Muscle Cross Sectional Area

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Specific Enzyme Activity

IUPAC Standards Online ◽

10.1515/iupac.90.0330 ◽

2019 ◽

Author(s):

Ján Labuda ◽

Richard P. Bowater ◽

Miroslav Fojta ◽

Günter Gauglitz ◽

Zdeněk Glatz ◽

...

Keyword(s):

Enzyme Activity ◽

Specific Enzyme ◽

Specific Enzyme Activity

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Preparation of gram quantities of a purified R-factor-mediated penicillinase from Escherichia coli strain W3310

Biochemical Journal ◽

10.1042/bj1300055 ◽

1972 ◽

Vol 130 (1) ◽

pp. 55-62 ◽

Cited By ~ 24

Author(s):

J. Melling ◽

G. K. Scott

Keyword(s):

Escherichia Coli ◽

Molecular Weight ◽

Enzyme Activity ◽

Coli Strain ◽

Specific Enzyme ◽

Specific Enzyme Activity ◽

E Coli ◽

R Factor

Purified penicillinase, in gram quantities, has been prepared from Escherichia coli strain W3310 by using methods developed to handle large amounts of material. The final product had a specific enzyme activity of 3.08 units/μg of protein, which was over twice as high as that reported previously (Datta & Richmond, 1966). The purified enzyme was similar to that from E. coli strain TEM, but different in molecular weight and some other respects. The differences observed may be a result of the greater purity obtained.

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Detection in HeLa cell extracts of a 7-methyl guanosine specific enzyme activity that cleaves m7GpppNm

Cell ◽

10.1016/0092-8674(75)90069-0 ◽

1975 ◽

Vol 6 (1) ◽

pp. 21-27 ◽

Cited By ~ 58

Author(s):

D.L. Nuss ◽

Y. Furuichi ◽

G. Koch ◽

A.J. Shatkin

Keyword(s):

Enzyme Activity ◽

Hela Cell ◽

Specific Enzyme ◽

Specific Enzyme Activity ◽

Cell Extracts

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Postnatal changes in cell body size and oxidative enzyme activity of spinal motoneurons innervating the rat tibialis anterior muscle

Developmental Brain Research ◽

10.1016/0165-3806(94)90176-7 ◽

1994 ◽

Vol 83 (1) ◽

pp. 28-34 ◽

Cited By ~ 2

Author(s):

Akihiko Ishihara ◽

Hisaya Tsuzimoto ◽

Hideki Suzuki ◽

Norikatsu Kasuga

Keyword(s):

Enzyme Activity ◽

Body Size ◽

Cell Body ◽

Tibialis Anterior ◽

Tibialis Anterior Muscle ◽

Oxidative Enzyme ◽

Spinal Motoneurons ◽

Oxidative Enzyme Activity ◽

Cell Body Size

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Further studies of L-arginine biosynthesis in germinating pea seeds. Evidence for the presence of argininosuccinate synthetase in cotyledon extracts

Canadian Journal of Biochemistry ◽

10.1139/o69-073 ◽

1969 ◽

Vol 47 (4) ◽

pp. 467-475 ◽

Cited By ~ 6

Author(s):

P. D. Shargool ◽

E. A. Cossins

Keyword(s):

Enzyme Activity ◽

Gel Filtration ◽

Magnesium Ions ◽

Argininosuccinate Synthetase ◽

Argininosuccinate Lyase ◽

Specific Enzyme ◽

Arginine Biosynthesis ◽

Specific Enzyme Activity ◽

Pea Seeds

The synthesis and metabolism of arginine in germinating peas was examined by supplying micromolar quantities of L-citruiline-carbamyl-14C, DL-arginine-carbamyl-14C, and DL-arginine-5-14C to imbibing seeds. Citrulline was readily incorporated into arginine, but the labelled arginine solutions were not extensively metabolized.Extracts of 1-day-old cotyledons were found to catalyze the synthesis of arginine from citrulline in a reaction having absolute requirements for ATP, L-aspartate, and magnesium ions. The extracts were fractionated by (NH4)2SO4 precipitation followed by gel filtration on columns of Sephadex G-50 and G-200. These treatments increased the specific enzyme activity by approximately 36 times. After such treatments the preparations still contained appreciable amounts of argininosuccinate lyase (L-argininosuccinate arginine-lyase, EC 4.3.2.1) activity. The rate of arginine synthesis was altered by increasing the concentrations of L-citrulline, L-aspartate, and ATP. The latter compounds were found to be inhibitory at concentrations of 1 μmole/ml and 4 μmoles/ml, respectively. Arginine synthesis was markedly affected by pH and by additions of arginine and argininosuccinate. It is concluded that germinating pea cotyledons contain appreciable levels of argirrinosuccmate synthetase (L-citrulline:L-aspartate ligase (AMP), EC 6.3.4.5), and furthermore, that this enzyme has importance in arginine biosynthesis during germination.

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