scholarly journals Regulatory properties of AMP deaminase isoenzymes from rabbit red muscle

1987 ◽  
Vol 242 (3) ◽  
pp. 875-879 ◽  
Author(s):  
A Raggi ◽  
M Ranieri-Raggi
Keyword(s):  
Skeletal Muscle ◽  
Inhibitory Action ◽  
Ph Value ◽  
Velocity Curve ◽  
Amp Deaminase ◽  
Work Intensity ◽  
Red Muscle ◽  
Regulatory Properties ◽  
Optimal Ph

We examined the kinetic and regulatory properties of the two isoenzymes of red muscle AMP deaminase, forms A and B, corresponding respectively to the single isoenzymes present in the heart and white skeletal muscle. At the optimal pH value, 6.5, both enzymes show hyperbolic substrate-velocity curves and are inhibited by GTP, inducing sigmoid kinetics. An effect similar to that of GTP is exerted on form B by ATP, whereas form A is almost insensitive to this nucleotide. At pH 7.1 both enzymes follow sigmoid kinetics. ATP enhances the sigmoidicity of the substrate-velocity curve of form B, but it stimulates form A, reverting sigmoidal to hyperbolic kinetics shown by the enzyme at optimal pH. At pH 7.1, form A is also less sensitive to the inhibitory action of Pi and GTP. These results suggest that, owing to the presence of form A, AMP deamination occurs in red muscle also at moderate work intensity. A possible role of this process in counteracting the production of adenosine by 5′-nucleotidase is hypothesized.

scholarly journals Role of insulin on exercise-induced GLUT-4 protein expression and glycogen supercompensation in rat skeletal muscle

2004 ◽  
Vol 96 (2) ◽  
pp. 621-627 ◽  
Author(s):  
Chia-Hua Kuo ◽  
Hyonson Hwang ◽  
Man-Cheong Lee ◽  
Arthur L. Castle ◽  
John L. Ivy
Keyword(s):  
Skeletal Muscle ◽  
Protein Expression ◽  
Muscle Glycogen ◽  
White Muscle ◽  
Insulin Response ◽  
Exercise Session ◽  
Carbohydrate Supplementation ◽  
Glut 4 ◽  
Red Muscle

The purpose of this study was to investigate the role of insulin on skeletal muscle GLUT-4 protein expression and glycogen storage after postexercise carbohydrate supplementation. Male Sprague-Dawley rats were randomly assigned to one of six treatment groups: sedentary control (Con), Con with streptozocin (Stz/C), immediately postexercise (Ex0), Ex0 with Stz (Stz/Ex0), 5-h postexercise (Ex5), and Ex5 with Stz (Stz/Ex5). Rats were exercised by swimming (2 bouts of 3 h) and carbohydrate supplemented immediately after each exercise session by glucose intubation (1 ml of a 50% wt/vol). Stz was administered 72-h before exercise, which resulted in hyperglycemia and elimination of the insulin response to the carbohydrate supplement. GLUT-4 protein of Ex0 rats was 30% above Con in fast-twitch (FT) red and 21% above Con in FT white muscle. In Ex5, GLUT-4 protein was 52% above Con in FT red and 47% above Con in FT white muscle. Muscle glycogen in FT red and white muscle was also increased above Con in Ex5 rats. Neither GLUT-4 protein nor muscle glycogen was increased above Con in Stz/Ex0 or Stz/Ex5 rats. GLUT-4 mRNA in FT red muscle of Ex0 rats was 61% above Con but only 33% above Con in Ex5 rats. GLUT-4 mRNA in FT red muscle of Stz/C and Stz/Ex0 rats was similar but significantly elevated in Ex5/Stz rats. These results suggest that insulin is essential for the increase in GLUT-4 protein expression following postexercise carbohydrate supplementation.

scholarly journals Developmental forms of human skeletal-muscle AMP deaminase. The kinetic and regulatory properties of the enzyme

1988 ◽  
Vol 249 (1) ◽  
pp. 255-261 ◽  
Author(s):  
K Kaletha ◽  
G Nowak
Keyword(s):  
Skeletal Muscle ◽  
Human Fetus ◽  
Human Skeletal Muscle ◽  
Fetal Tissue ◽  
Amp Deaminase ◽  
Half Saturation Constant ◽  
Substrate Saturation ◽  
Regulatory Ligands ◽  
Regulatory Properties ◽  
Similar Kinetic

AMP deaminase isoforms from human skeletal muscle can be separated chromatographically [Kaletha, Spychała & Nowak (1987) Experientia 43, 440-443]. In adult tissue nearly all the AMP deaminase activity was eluted from phosphocellulose with 0.75 M-KCl (‘adult’ isoform), and the remaining activity could be eluted with 2.0 M-KCl. Conversely, most of the AMP deaminase activity from 11-week-old fetal tissue was eluted from phosphocellulose with 2.0 M-KCl (‘fetal’ isoform). In the present paper the kinetic and regulatory properties of AMP deaminase extracted from 11- and 16-week-old fetal skeletal muscle are reported. The two isoforms from 11-week-old human fetus differed distinctly in these properties. The ‘fetal’ isoform had about 5-fold higher half-saturation constant (S0.5) value than the ‘adult’ form. It was also more sensitive to the influence of some important regulatory ligands (ADP, ATP and Pi), and exhibited a different pH/activity profile. The ‘adult’ isoform of AMP deaminase from fetal muscle and the enzyme from mature muscle possessed similar kinetic and regulatory properties. This isoform seems not to be subject to any major modifications during further ontogenesis. This is not true, however, for the ‘fetal’ isoform. In the muscle of 16-week-old human fetus, the ‘fetal’ isoform showed a peculiar, biphasic, type of substrate-saturation kinetics. This phenomenon may reflect appearance of the next, developmentally programmed, isoform of human skeletal-muscle AMP deaminase.

Adaptation of rat skeletal muscle to creatine depletion: AMP deaminase and AMP deamination

1992 ◽  
Vol 73 (6) ◽  
pp. 2713-2716 ◽  
Author(s):  
J. M. Ren ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Contractile Activity ◽  
Activity Level ◽  
Amp Deaminase ◽  
Slow Twitch Muscle ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Similar Decrease

AMP deaminase catalyzes deamination of the AMP formed in contracting muscles to inosine 5′-monophosphate (IMP). Slow-twitch muscle has only approximately 30% as high a level of AMP deaminase activity as fast-twitch muscle in the rat, and rates of IMP formation during intense contractile activity are much lower in slow-twitch muscle. We found that feeding the creatine analogue beta-guanidinopropionic acid (beta-GPA) to rats, which results in creatine depletion, causes a large decrease in muscle AMP deaminase. This adaptation was used to evaluate the role of AMP deaminase activity level in accounting for differences in IMP production in slow-twitch and fast-twitch muscles. beta-GPA feeding for 3 wk lowered AMP deaminase activity in fast-twitch epitrochlearis muscle to a level similar to that found in the normal slow-twitch soleus muscle but had no effect on the magnitude of the increase in IMP in response to intense contractile activity. Despite a similar decrease in ATP in the normal soleus and the epitrochlearis from beta-GPA-fed rats, the increase in IMP was only approximately 30% as great in the soleus in response to intense contractile activity. These results demonstrate that the accumulation of less IMP in slow- compared with fast-twitch skeletal muscle during contractile activity is not due to the lower level of AMP deaminase in slow-twitch muscle.

scholarly journals The Role of Histidine-Proline-Rich Glycoprotein as Zinc Chaperone for Skeletal Muscle AMP Deaminase

Biomolecules ◽  
2014 ◽  
Vol 4 (2) ◽  
pp. 474-497 ◽  
Author(s):  
Maria Ranieri-Raggi ◽  
Arthur Moir ◽  
Antonio Raggi
Keyword(s):  
Skeletal Muscle ◽  
Amp Deaminase

scholarly journals Adenylate metabolism in the heart. Regulatory properties of rabbit cardiac adenylate deaminase

1979 ◽  
Vol 182 (2) ◽  
pp. 361-366 ◽  
Author(s):  
R Barsacchi ◽  
M Ranieri-Raggi ◽  
C Bergamini ◽  
A Raggi
Keyword(s):  
Skeletal Muscle ◽  
Kinetic Properties ◽  
Amp Deaminase ◽  
Alkaline Ph ◽  
Muscle Enzyme ◽  
Adenylate Deaminase ◽  
Activated State ◽  
Maximal Activation ◽  
Regulatory Properties

The kinetic properties of a 300-fold purified cardiac AMP deaminase were studied and compared with those of the corresponding enzyme from skeletal muscle. The heart enzyme is activated by ATP and less efficiently by ADP, and is inhibited by Pi, phosphocreatine and GTP. ATP, even at micromolar concentrations, is able to abolish the effects of the inhibitors. The affinity of the enzyme for AMP is low in the absence of activators (Km 3.1 mM), but, in the presence of ATP, becomes as high as that of skeletal-muscle AMP deaminase (Km 0.4 mM). The maximal activation by ATP is observed at alkaline pH (pH 7.5-8.0). Under the same conditions ATP is maximally inhibitory for skeletal-muscle enzyme. These results suggest that AMP deaminase in the heart is always in the activated state, whereas in skeletal muscle the enzyme is active only during exhaustive contractions.

Sign in / Sign up

Export Citation Format

Share Document