Lactic acid formation

High OH concentrations and the presence of Ca2+, rather than monovalent cations, favor route 2 over 4a (that is, lactic acid formation is favored by high pH),... 

B2. Barron, E. S. G., and Harrop, G. A., The effect of methylene blue and other dyes upon the glycolysis and lactic acid formation of mammalian and avian erythrocytes. J. Biol. Chetn. 79, 65-87 (1028). 

Lundsgaard, E. (1930). Experiments on muscle contraction without lactic acid formation. Biochem. Z. 217, 162-177. 

Under the conditions when protons accumulate in muscle, the physical activity of muscle is decreased by fatigue, hence the rate of ATP utilisation and, therefore, ATP generation via glycolysis, are decreased. Consequently the rate of lactic acid formation is decreased. It is unclear it protons are directly involved in fatigue. It is discussed in Chapter 13. 

Young et al. [43] chose an alternative approach to prediction of ultimate pH. They measured the concentration of the muscle glycogen responsible for lactic acid formation. This was done immediately after slaughter. The glycogen concentration, expressed as glucose equivalents per gram of muscle, has a curvilinear relationship to ultimate pH (Fig. 28.1). 

Lactic acid formation occurred to a different extent when paper sludge hydrolysate was used. Although the same batch of hydrolysate was used for all experiments under identical conditions, lactate production was observed from the early stage (Fig. 2, condition D2) of the fermentation or lactate was only found in the fermentation broth in the very late phase of the process (condition Dl). 

Several studies (13,14) have indicated that cheese whey could also be used as feedstock for the production of nisin given supplementation of some essential nutrients. However, the systematic investigation of lactic acid formation accompanied by nisin biosynthesis, and the possibility of the simultaneous production of nisin and lactic acid, have not been reported. 

The significance of yeast extract and KH2P04 for lactic acid formation indicates the important role of protein and inorganic phosphate in the metabolism of L. lactis. The lesser influence of polypeptone compared with yeast extract proves that yeast extract is a good nitrogen source for nisin and lactic acid production. The influences of pH and temperature were not significant in this screening experiment, because this test was carried out close to the optimal conditions of these two variables (16). 

The optimal conditions for nisin biosynthesis and lactic acid formation were obtained by further numerical analysis of the response surface using Design-Expert software and are presented in Table 7. The solution to the maximal nisin biosynthesis was 12.04 g/L for yeast extract, 0.57 g/L for KH2P04, and 0.57 g/L for MgS04. The solution to the maximal lactic acid production was 11.78 g/L for yeast extract, 0.64 g/L for KH2P04, and 0.63... 

Discovery of yeast as the origin of fermentation (Erxleben) Scientific explanation of lactic acid formation (Pasteur)... 

L-Lactic acid formation by fermentation of glucose or lactose Lactobacillus... 

CH3CO3CCH3 (acetic anhydride) Formation of 14.6.5.3. CH3CHOHCO2H (lactic acid) Formation of 14.3.6,2.4. 

A combined respiratory-metabolic acidosis occurs due to hypercapnia and lactic acid formation. Death may occur. Naloxone (0.4 to 2 mg IV) reverses the propoxyphene-induced respiratory depression. 

Figure 23.30 During strenuous activity, oxygen can be depieted in cells. Then, energy is produced without oxygen and lactic acid is produced. Soreness in muscles a day or two after the activity is a sign of lactic acid formation. 

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