Aerobic glycolysis oxidation

The major biochemical features of neutrophils are summarized in Table 52-8. Prominent feamres are active aerobic glycolysis, active pentose phosphate pathway, moderately active oxidative phosphorylation (because mitochondria are relatively sparse), and a high content of lysosomal enzymes. Many of the enzymes listed in Table 52-4 are also of importance in the oxidative metabolism of neutrophils (see below). Table 52-9 summarizes the functions of some proteins that are relatively unique to neutrophils. 

The electron transport chain gets its substrates from the NADH and FADH2 supplied by the TCA cycle. Since the TCA cycle and electron transport are both mitochondrial, the NADH generated by the TCA cycle can feed directly into oxidative phosphorylation. NADH that is generated outside the mitochondria (for example, in aerobic glycolysis) is not transported directly into the mitochondria and oxidized—that would be too easy. 

C5a and C5a des Arg stimulate aerobic glycolysis, hexose monophosphate shunt activity, glucose uptake and the respiratory burst of human neutrophils. All of these processes are stimulated in neutrophil suspensions incubated in the absence of cytochalasin B, but the responses are considerably enhanced if this inhibitor of microtubule assembly is present. Stimulated rates of oxidative metabolism are maximal within 2 min of addition of peptides, with half-maximal responses obtained at 30-60 nM C5a and 1-3 pM C5a des Arg. 

Berberine inhibits oxidative decarboxylation of yeast pyruvic acid (310) the same dose has, however, no effect upon aerobic glycolysis, Warburg s respiratory enzymes, indophenol oxidase, etc. Berberine and tetrahydroberberine have an inhibitory effect on oxidation of (+ )-alanine in rat kidney homogenates (498). Berberine and palmatine show a specific inhibitory effect upon cholinesterase in rabbit spleen and on pseudocholinesterase in horse serum (499). Berberine inhibits cellular respiration in ascitic tumors and even in tissue cultures (500-502). The specific toxic effect of berberine on the respiration of cells of ascitic tumors in mice was described (310). The glycolysis was not found to be affected, but the uptake of oxygen was smaller. Fluorescence was used in order to demonstrate berberine in cellular granules. Hirsch (503) assumed that respiration is inhibited by the effect of berberine on the yellow respiratory enzymes. Since the tumorous tissue contains a smaller number of yellow respiratory enzymes than normal tissue it is more readily affected by berberine. Subcutaneous injections of berberine, palmatine, or tetrahydropalmatine significantly reduce the content of ascorbic acid in the suprarenals, which is not affected by hypophysectomy (504). 

Chemically induced cardiac failure has been the subject of a number of works. Balazs and Ferrans (1978), Baskin (1991), and Acosta (2001) give an overview of the subject. Hypoxia is one of the effects of the decreased availability of ATP which depresses contraction in the muscle. The energy that is supplied by the phosphate bonds is possible only as long as aerobic glycolysis and oxidative phosphorylation are maintained. Under anoxic conditions, this is no longer possible and with the adrenergic stimulus continuing, calcium accumulation in the mitochondria leads to... 

Pentamidine, an aromatic diamine, has been known since the late 1930s as a treatment for trypanosomiasis and some forms of leishmaniasis. In recent times it has been extensively used in the treatment of Pneumocystis jiroveci pneumonia. Its mechanism of action is probably related to inhibition of dihydrofolate reductase and inhibition of oxidative phosphorylation and nucleic acid synthesis, as well as an effect on aerobic glycolysis. 

The answer is b. (Murray, pp 123-148. Scriver, pp 2367-2424. Sack, pp 159-175. Wilson, pp 287-317.) Aerobic glycolysis can be defined as the oxidative conversion of glucose to two molecules of pyruvate. In the process, two molecules of ATP and two molecules of NADH are produced. Since reducing equivalents from the two molecules of NADH produced in the cytoplasm must be transported into the mitochondrion for oxidation, it is not known how many ATP molecules are produced. On the assumption that two ATP molecules are formed per molecule of NADH oxidized via the glycerol phosphate shuttle, the ATP yield in aerobic glycolysis can be calculated as six ATP molecules per mole of glucose utilized. 

Aerobic glycolysis as occurs in normal cells would eventually involve the complete oxidation or conversion of glucose to carbon dioxide and water, yielding enCTgy in the process. That is, in simplest terms, the overall conversion can be written as... 

Glycolysis produces NADH from NAD in Reaction 6 (G3P <=> 1,3BPG). In aerobic glycolysis, NADH is converted to NAD+ by the processes of electron transport and oxidative phosphorylation, which occur in the mitochondria. If oxygen is limiting (such as during heavy exercise), oxidative phosphorylation does not occur and NADH is not converted to NAD+. This could be disastrous if there were no other way to produce NAD... 

Respiration (oxidative breakdown and energy release by reaction with oxygen) Respiration Using Oxygen = Aerobic Glycolysis... 

Robinson GL, Dinsdale D, MacFarlane M, Cain K. Switching from aerobic glycolysis to oxidative phosphorylation modulates the sensitivity of mantle lymphoma cells to TRAIL. Oncogene. 2012 31 4996-5006. 

Glucose oxidation in animal cells consists of two successive parts (11.1) aerobic glycolysis (11.2) respiration. Glycolysis takes place in 11 successive steps each involving a different phosphate ester and each catalysed by an appropriate enzyme (Table 11.19). The penultimate product is pyruvic acid (usually referred to as pyruvate) and the overall scheme can be represented by... 

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