Biochemical Perspective

The most important oxidation from a biochemical perspective is the conversion of thiols to disulfides... 

Mann, S. (1989) Biomineralization Chemical and Biochemical Perspectives (eds S. Mann, J. Webb, R.J.P. Williams), VCH, Weinheim, Chapter 2. 

This section of the review will consider various types of biotransformations of alkaloids from both chemical and biochemical perspectives. We have attempted to avoid serious repetition of published work previously covered by Holland (2) in this series by presenting material published since 1980 and by inclusion of a few examples that were not mentioned earlier. For convenience, we have organized our review in essentially the same style used by Holland. 

Mann, S. Frankel, R.B. (1989) Magnetite biomineralization in unicellular microorganisms. In Mann, S. Webb, J. Williams, R.J.P. (eds.) Biomineralization Chemical and biochemical perspectives. VCH Weinheim, 389-426... 

G.L. Grandjean, E. (eds.) Mdssbauer spectroscopy applied to inorganic chemistry. Plenum Publ. Corp., 3 417-444 Webb, J. Macey, D.J. Mann, S. (1989) Biomineralization of iron in molluscan teeth. In Mann, S. Webb, J. Williams, R.J.P. (eds.) Biomineralization Chemical and biochemical perspectives. VCH Weinheim, 345-387 Webster, J.G. Swedlund, P.J. Webster, K.S. (1998) Trace metal adsorption onto an acid mine drainage iron(lll) oxy hydroxy sulfate. Environ. Sci.Techn. 32 1361-1368 Wedepohl, K.H. (1969) Composition and abundance of common igneous rocks. In Wedepohl, K.H. (ed.) Handbook of geochemistry. Springer, Berlin, 1 227-249 Wedepohl, K.H. (1969a) Composition and abundance of common sedimentary rocks. 

The review Double bonds from a biochemical perspective 3 summarizes the importance of the biochemical reactions of selected groups of physiologically active unsaturated compounds, e.g. those that react with the amino groups of amino acids, polyunsaturated fatty acids and vitamin A. 

Mann S, Webb J, Williams RJP (eds.) (1989) Biomineralization chemical and biochemical perspectives. Wiley, Weinheim... 

Gershenzon, J., The cost of plant chemical defense against herbivory a biochemical perspective, in Insect-Plant Interactions, Vol. 5, Bernays, E.A., Ed., CRC Press, Boca Raton, FL, 1994, chap. 5. 

The primary goal of therapy is the control of the hypercholesterolemia and prevention of atherosclerotic cardiovascular disease. Patients with heterozygous FH can usually be successfully treated with medications to lower the LDL cholesterol to acceptable levels (Table 14-2). They are generally responsive to treatment with statins, alone or in combination with other drugs, such as bile acid sequestrants (such as cholestyramine) or cholesterol absorption inhibitors (such as ezetimibe) that act additively to upregulate the expression of the functioning LDL receptor as described in the Biochemical Perspectives section. In a few cases, a more aggressive treatment with LDL apheresis (discussed in this section) may have to be considered in order to reach acceptable LDL cholesterol levels. 

I-cell disease is suspected clinically by the phenotype and is confirmed biochemically (cf. Biochemical Perspectives section). The infant with I-cell disease is usually small for gestational age and is clinically differentiated from having Hurler s syndrome by earlier onset of signs and symptoms, the absence of excessive mu-copolysacchariduria, short stature, and the rapidly progressive course, leading to death usually by age 4 years. 

Prenatal diagnosis of I-cell disease has been based on greatly reduced phosphotransferase activity (cf. Biochemical Perspectives section) and abnormal intracellular-extracellular distribution of lysosomal enzymes in cultured amni-otic fluid cells (Table 17-3).As indicated in Table 17-3, amniotic fluid cells secrete large amounts of lysosomal enzymes into the extracellular medium. Decreased levels of lysosomal enzymes in chorionic villi obtained by biopsy have also been observed in I-cell disease however, the characteristic secondary effect (i.e.,increased levels of lysosomal enzymes in the extracellular compartment) is only partially expressed or not expressed at all in chorionic villi, suggesting an alternative mechanism for the transport of lysosomal proteins. Although... 

Indirect indicators of vitamin B12 deficiency include measurements of the metabolites homocysteine and methylmalonic acid (MMA) in serum and MMA in urine (see the Biochemical Perspectives section). Whereas the serum homocysteine concentration increases during folate or vitamin B12 deficiencies, the serum and urine MMA concentrations increase only in vitamin B12 deficiency. Therefore, MMA determinations can be used to differentiate vitamin B12 deficiency from folate deficiency. The normal concentration of MMA in serum ranges from 0.08 to 0.28 pmol/L. MMA is quantified using gas-liquid chromatography and mass spectrometry. Elevated concentrations of MMA and homocysteine in serum may precede the development of hematological abnormalities and reductions in serum vitamin B12 concentrations. One should be aware that other conditions, including renal in sufficiency and inborn errors of metabolism, can also result in elevated serum levels of MMA. 

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