High-energy phosphate metabolism

Kato, T., Shioiri, T., Murashita, J., Hamakawa, H., Takahashi, Y., Inubushi, T., and Takahashi, S. (1995) Lateralized abnormality of high energy phosphate metabolism in the frontal lobes of patients with bipolar disorder detected by phase-encoded 31P-MRS. Psychol Med 25 557—566. 

A magnetic resonance spectroscopy (MRS) study examined correlates of repetitive violence in 13 mildly mentally retarded individuals and 14 controls (Critch-ley et al., 2000). Concentrations and ratios of N-acetyl aspartate (NAA) and creatine phosphocreatine (Cr-l-PCr) were assayed. The NAA and CR-I-CR concentrations reflect neuronal density and high-energy phosphate metabolism, respectively. Violent patients had lower prefrontal concentrations of NAA and Cr-l-PCr and a lower NAA/Cr-l-PCr ratio in the amyg-dalohippocampal complex than that in controls. Within the violent group, prefrontal NAA concentration correlated with aggression frequency. 

Pettegrew J. W., Klunk W. E., Kanal E., Panchalingam K., and McClure R. J. (1995). Changes in brain membrane phospholipid and high-energy phosphate metabolism precede dementia. Neurobiol. Aging 16 973-975. 

Gangadhar BN, Jayakumar PN, Subbakrishna DK, Janakira-maiah N, Keshavan MS. 2004. Basal ganglia high-energy phosphate metabolism in neuroleptic-naive patients with schizophrenia A 31-phosphorus magnetic resonance spectroscopic study. Am J Psychiatry 161 1304-1306. 

Yacubian J, De Castro CC, Ometto M, Barbosa E, De Camargo CP, et al. 2002. 31p-spectroscopy of frontal lobe in schizophrenia Alterations in phospholipid and high-energy phosphate metabolism. Schizophr Res 58 117-122. 

Several disorders can impair ventricular function and play a role in the development of DHF. DHF is seen often in patients with hypertension, coronary artery disease (CAD), valvular heart disease, and hypertrophic cardiomyopathies. Hypertension is the most common underlying cardiovascular disorder in patients with DHF. There are several proposed mechanisms by which hypertension may impair diastolic function. Hypertension can alter diastolic function through its effects on (1) wall tension, (2) myocardial hypertrophy and fibrosis, and (3) small vessel structure and function, and (4) by predisposing to epicardial CAD. An association between impaired LV filling and subnormal high-energy phosphate metabolism has been shown in hypertensive patients, even in the absence of left ventricular hypertrophy (LVH). ... 

Mitochondria Mitochondria are organelles surrounded by two membranes that differ markedly in their protein and lipid composition. The inner membrane and its interior volume, the matrix, contain many important enzymes of energy metabolism. Mitochondria are about the size of bacteria, 1 fim. Cells contain hundreds of mitochondria, which collectively occupy about one-fifth of the cell volume. Mitochondria are the power plants of eukaryotic cells where carbohydrates, fats, and amino acids are oxidized to CO9 and H9O. The energy released is trapped as high-energy phosphate bonds in ATR... 

Pettegrew, J. W., Keshavan, M. S., Panchalingam, K. et al. Alterations in brain high-energy phosphate and membrane phospholipid metabolism in first-episode, drug-naive schizophrenics. A pilot study of the dorsal prefrontal cortex by in vivo phosphorus 31 nuclear magnetic resonance spectroscopy. Arch. Gen. Psychiat. 48 563-568,1991. 

About 10% of the acid-soluble phosphorus of the red blood cells in galactosemia is accounted for by galactose-l-phosphate. Since all this is derived from adenosine triphosphate by reaction (1), it represents the tying up in a metabolically useless form of a high proportion of the high-energy phosphate of the erythrocyte. Untreated galactosemics have... 

Other nuclei, such as 13C or 31P, may be used to study other metabolite pools, or they can complement H-NMR to create more sophisticated NMR spectra. 13C-NMR provides a greater spectral range ( 200 ppm) than H-NMR ( 15 ppm). Although lower natural abundance of 13C (1.1%) yields lower sensitivity, it also provides an opportunity to use isotopic enrichment to trace specific metabolic pathways with enhanced sensitivity.4 31P can observe high-energy phosphate metabolites such as adenosine triphosphate. 

Magnesium ion is usually involved (for charge neutralization ) where high-energy phosphate is moved from one molecule to another by an enzyme, i.e., the metabolically active form of ATP is usually the magnesium chelate. 

Nucleotides are the building blocks for nucleic acids they are also involved in a wide variety of metabolic processes. They serve as the carriers of high-energy phosphate and as the precursors of several coenzymes and regulatory small molecules. Nucleotides can be synthesized de novo from small-molecule precursors or, through salvage pathways, from the partial breakdown products of nucleic acids. The highlights of our discussion in this chapter are as follows. 

Another physiologically important anion is phosphate which is essential for bone formation, for the buffering of biological fluids and as a component of numerous enzyme systems. Intermediary metabolism and, in particular, carbohydrate utilisation are intricately interwoven with the phosphate cycle through the reversible conversion of inorganic phosphate to high energy phosphate in ATP. 

DNP is an oxidative phosphorylation uncoupler. It makes the process only about 40% efficient by uncoupling a high energy phosphate molecule from ATP and therefore turning ATP into ADP. To maintain an adequate supply of ATP, the body must step-up production. For this reason metabolism is significantly increased and an incredible amount of calories are burned. During this accelerated metabolic state, and due to the need for ATP production, most of the calories come from fatty acids (adipose/fat tissue). So little or no muscle is lost (With adequate protein intake). 

---