Pyruvate kinase: modulation by L-phenylalanine and L-alanine

1969 ◽  
Vol 47 (9) ◽  
pp. 895-898 ◽  
Author(s):  
R. Vijayvargiya ◽  
W. S. Schwark ◽  
R. L. Singhal
Keyword(s):  
Skeletal Muscle ◽  
Pyruvate Kinase ◽  
Kinase Activity ◽  
Competitive Inhibitor ◽  
Seminal Vesicles ◽  
Appreciable Effect ◽  
Pyruvate Kinase Activity ◽  
Rat Prostate

L-Phenylalanine was found to be a competitive inhibitor of pyruvate kinase in the rat prostate, seminal vesicles, uterus, and skeletal muscle. In contrast, L-alanine exerted no appreciable effect on pyruvate kinase activity but was capable of protecting against, as well as reversing, the inhibition produced by L-phenylalanine. The results suggest that the interactions between L-phenylalanine and L-alanine are important to the regulation of pyruvate kinase activity in tissues containing the M-type isozyme.

Metabolie control mechanisms in mammalian systems. XI Pyruvate kinase modulation in the rat prostate and seminal vesicles

1970 ◽  
Vol 48 (11) ◽  
pp. 1268-1277 ◽  
Author(s):  
R. Vijayvargiya ◽  
W. S. Schwark ◽  
Radhey L. Singhal
Keyword(s):  
Pyruvate Kinase ◽  
Kinase Activity ◽  
Thermal Inactivation ◽  
Prostate Gland ◽  
Competitive Inhibitor ◽  
Seminal Vesicles ◽  
Control Mechanisms ◽  
Pyruvate Kinase Activity ◽  
Dependent Inhibition ◽  
Rat Prostate

The modulation of pyruvate kinase activity by several metabolites has been investigated in the prostate gland and seminal vesicles of normal mature rats. Whereas direct addition of fructose 1,6-diphosphate to the reaction mixture exerted no effect on pyruvate kinase activity, slight activation of the prostatic and seminal vesicular enzyme was produced by L-alanine. Pyruvate kinase activity in both accessory sexual tissues was rapidly inactivated by incubation of the supernatant fluids at 37 °C; this inactivation was prevented by L-alanine. Whereas L-phenylalanine was found to be a competitive inhibitor of prostatic and vesicular pyruvate kinase, L-alanine was capable of preventing and reversing the inhibition produced by L-phenylalanine. Pyruvate kinase activity in both tissues was also inhibited by Cu2+ in concentrations as low as 0.005 mM; 50% inhibition of the enzyme was produced by 0.2 mM Cu2+. Addition of L-alanine prevented as well as reversed the inhibition produced by low concentrations of this cation.The sulfhydryl inhibitor, p-CMB, produced a dose-dependent inhibition of prostatic and vesicular pyruvate kinase whereas addition of penicillamine resulted in a slight activation of the enzyme. In addition, penicillamine effectively reversed the inhibition produced by p-CMB as well as by Cu2+. The thermal inactivation of pyruvate kinase activity in accessory sexual tissues was also prevented effectively when the supernatant fluids were preincubated in the presence of penicillamine.

scholarly journals Adipose-tissue pyruvate kinase. Properties and interconversion of two active forms

1968 ◽  
Vol 110 (1) ◽  
pp. 67-77 ◽  
Author(s):  
C I Pogson
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Pyruvate Kinase ◽  
Kinase Activity ◽  
Deae Cellulose ◽  
Epididymal Adipose Tissue ◽  
Partial Purification ◽  
Pyruvate Kinase Activity ◽  
Bivalent Cation

1. Extraction of rat epididymal adipose tissue with buffer containing EDTA yields a pyruvate kinase, provisionally called PyK-A, the properties of which resemble in several respects those of the allosteric pyruvate kinase of liver. These properties include co-operative interactions with phosphoenolpyruvate, Mg2+, K+, NH4+ and ATP, and sensitivity to activation by fructose 1,6-diphosphate. 2. Extraction in the absence of EDTA yields predominantly a form, PyK-B, that shows both normal Michaelis–Menten kinetics with phosphoenolpyruvate, Mg2+ and ATP, and co-operative interactions with K+ and NH4+; this form is insensitive towards fructose 1,6-diphosphate. 3. Both forms yield simple kinetics with ADP, though Km values differ in the two systems. In all cases where co-operativity has been demonstrated, Hill-plot n values are between 1·4 and 2·0. 4. The conversion of PyK-A into PyK-B is mediated specifically by fructose 1,6-diphosphate; the reverse reaction is occasioned by EDTA, ATP or citrate. It is thought that a bivalent cation may be involved in this interconversion. 5. Attempts at partial purification have revealed that the enzyme resembles the pyruvate kinase of skeletal muscle, rather than that of liver, in its solubility in ammonium sulphate and elution from DEAE-cellulose. 6. The relevance of these properties in the regulation of pyruvate kinase activity in vivo in adipose tissue is discussed.

Red blood cell age, pyruvate kinase activity, and insulin receptors. Evidence that monocytes and RBCs may behave differently

Diabetes ◽  
1983 ◽  
Vol 32 (11) ◽  
pp. 1017-1022 ◽  
Author(s):  
A. Camagna ◽  
R. De Pirro ◽  
L. Tardella ◽  
L. Rossetti ◽  
R. Lauro ◽  
...  
Keyword(s):  
Blood Cell ◽  
Pyruvate Kinase ◽  
Red Blood Cell ◽  
Kinase Activity ◽  
Insulin Receptors ◽  
Pyruvate Kinase Activity ◽  
Cell Age

Red Blood Cell Age, Pyruvate Kinase Activity, and Insulin Receptors: Evidence that Monocytes and RBCs May Behave Differently

Diabetes ◽  
1983 ◽  
Vol 32 (11) ◽  
pp. 1017-1022 ◽  
Author(s):  
A. Camagna ◽  
R. D. Pirro ◽  
L. Tardella ◽  
L. Rossetti ◽  
R. Lauro ◽  
...  
Keyword(s):  
Blood Cell ◽  
Pyruvate Kinase ◽  
Red Blood Cell ◽  
Kinase Activity ◽  
Insulin Receptors ◽  
Pyruvate Kinase Activity ◽  
Cell Age

Pyruvate kinase activity in cerebral hemispheres and cerebellum-brainstem of normal and hypoxic-ischemic newborn rats

2004 ◽  
Vol 3 (3) ◽  
pp. 152-155 ◽  
Author(s):  
Hacer Yapicioglu ◽  
Mehmet Satar ◽  
Nejat Narli ◽  
Levent Kayrin ◽  
Ercan Tutak
Keyword(s):  
Pyruvate Kinase ◽  
Kinase Activity ◽  
Cerebral Hemispheres ◽  
Newborn Rats ◽  
Pyruvate Kinase Activity

Superoxide dismutase and cytochrome oxidase in collapsed lungs: possible role in reexpansion edema

1988 ◽  
Vol 65 (1) ◽  
pp. 235-241 ◽  
Author(s):  
R. M. Jackson ◽  
A. L. Brannen ◽  
C. F. Veal ◽  
J. D. Fulmer
Keyword(s):  
Superoxide Dismutase ◽  
Cytochrome Oxidase ◽  
Pyruvate Kinase ◽  
Kinase Activity ◽  
H2o2 Production ◽  
Lung Collapse ◽  
Pyruvate Kinase Activity ◽  
Sod Activity ◽  
Control Rabbit ◽  
Radical Production

This study examined the effects of lung collapse, a condition that causes relative hypoxia in lung tissues, on superoxide dismutase (SOD), cytochrome oxidase (cyt ox), and pyruvate kinase (py ki) activities in rabbits. Cyanide-insensitive respiration measurements were done in collapsed and contralateral lungs, as an index of intracellular free radical production. Rabbits' right lungs were collapsed for 7 days after which the animals were killed. We found that control rabbit lungs contained approximately 25 SOD units/mg DNA measured with 10(-5) M KCN (total SOD) and approximately 11 SOD units/mg DNA measured with 10(-3) M KCN (mitochondrial or MnSOD). Right lung collapse caused a 25% decrease in mitochondrial SOD activity after 7 days (P less than 0.05), whereas no significant changes occurred in right or left lungs' total SOD activity. In control rabbits cyt ox activity averaged approximately 0.009 mumol ferrocytochrome c.min-1.mg DNA-1. Right lung collapse caused a greater than 40% decrease in cyt ox activity after 7 days of collapse (P less than 0.05), whereas cyt ox activity in contralateral left lungs did not change. Pyruvate kinase activity, a marker for anaerobic glycolysis resulting from tissue hypoxia, increased 49% in collapsed right lungs (P less than 0.01). Cyanide-insensitive respiration was 83% higher in 7 day-collapsed lungs (2.28 +/- 0.66 microliters O2.min-1.g-1) compared with contralateral lungs (1.24 +/- 0.34, P less than 0.05), indicating increased O2-. and H2O2 production in this tissue after homogenization at normoxic PO2 (approximately 150 Torr).(ABSTRACT TRUNCATED AT 250 WORDS)

Sign in / Sign up

Export Citation Format

Share Document