Aspartate high concentration

Figures 11(a) and 11(b) [112] show the variation of Ni-Ge-P deposition rate and Ge content as a function of aspartic acid and Ge(IV) concentration, respectively. A relatively low P content, ca. 1-2 at%, was observed in the case of films exhibiting a high concentration of Ge (> 18 at%). Like other members of its class, which includes molybdate and tungstate, Ge(IY) behaves a soft base according to the hard and soft acids and bases theory (HSAB) originated by Pearson [113, 114], capable of strong adsorption, or displaying inhibitor-like behavior, on soft acid metal surfaces. In weakly acidic solution, uncomplexed Ge(IV) most probably exists as the hydrated oxide, or Ge(OH)4, which, due to acid-base reactions, may be more accurately represented as [Gc(OH)4 nO ] ".

Zinc is important to the normal functioning of the central nervous system (CNS). At low concentrations, zinc protects mammalian brain neurons by blocking N-methyl-D-aspartate receptor-mediated toxicity. At high concentrations, zinc is a potent, rapidly acting neurotoxicant in the mammalian brain, as judged by zinc-induced neuronal injury of in vitro mature cortical cell cultures (Choi et al. 1988). Increased brain levels of zinc are associated with Pick s disease in certain strains of rodents with inherited epileptic seizures. Intravenous injection of zinc in rats with genetically inherited epilepsy produces seizures a similar response occurs with intracranial injection of zinc in rabbits with inherited audiogenic seizures (Choi et al. 1988). 

An excellent review on protein hydrolysis for amino acid composition analysis has been published by Eountoulakis and Lahm [190], Hydrolysis can be performed by either chemical (under either acidic or basic conditions) or enzymatic means. The acidic hydrolysis itself can be carried out in a liquid or a gas-phase mode. The conventional acid hydrolysis uses 6M HCl for 20-24 h at 110°C under vacuum [200], In these conditions, asparagine and glutamine are completely hydrolyzed to aspartic acid and glutamic acid, respectively. Tryptophan is completely destroyed (particularly in the presence of high concentrations of carbohydrate), while cysteine and sometimes methionine are partially oxidized. Tyrosine, serine, and threonine are partially destroyed or hydrolyzed and correction factors have to be applied for precise quantification [190,201],... 

Transaminases participate in metabolism of most of the amino acids, over 60 different enzymes have been identified.142163 Best studied are the aspartate aminotransferases, a pair of cytosolic and mitochondrial isoenzymes which can be isolated readily from animal hearts. Their presence in heart muscle and brain in high concentration is thought to be a result of their functioning in the malate-aspartate shuttle... 

In brain tissue, low concentrations of glutamate and aspartate perform as neurotransmitters, but at high concentration these amino acids act as neurotoxins. Major advances in the excitatory amino acid receptor field have come from the identification, characterization, and cloning of different families of receptors and transporters (Dingledine and McBain, 1999). These receptors and transporters are specialized... 

AST Aspartate aminotransferase is not as liver-specific it is also found in high concentrations in skeletal muscle and myocardium. 

Q4 Cardiac enzymes are released into the blood following heart muscle damage during a heart attack. Creatine kinase, particularly its MB isoenzyme, is one of the most specific of these enzymes, which reaches a peak 24 hours after infarction. It rises and then falls within the first 72 hours of the heart attack. Aspartate transaminase is also released, but levels of this enzyme can be raised in several other conditions, so it is less specific than creatine kinase MB. Troponin T is also specific for myocardial damage and is raised for approximately two weeks following infarction. Finding a high concentration of these enzymes in a patient s blood therefore supports the evidence obtained from the ECG and confirms that the patient has suffered a myocardial infarction. 

Cerebral damage following stroke has also been assessed by MR spectroscopy. This technique uses the same methods as MRI but the signal obtained is converted into chemical as opposed to spatial information. Proton MR spectroscopy allows in vivo measurement of N-acetyl-containing compounds, creatine, choline and lactate. The majority of the N-acetyl signal comes from N-acetyl aspartate (NAA), which is present in high concentrations in the brain. The function of NAA is unclear, but it is of particular interest in studies of the brain since it is located almost exclusively in neurons in the adult. Decreases in the NAA resonance peak in vivo indicate neuronal or axonal injury or loss. 

The SCM-cysteine content of the SCMKB proteins ranges between that of wool itself and double this value. Compared with wool these proteins contain high concentrations of proline, serine, and threonine, but low concentrations of aspartic acid, glutamic acid, histidine, lysine, and leucine. In general, reverse trends are shown by the amino acid analyses for SCMKA fractions. SCMKB2 and SCM feather rachis are unique in that they contain virtually no histidine or lysine. In this respect they resemble... 

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