Enzymic activities, distribution

Several biochemical events occur posttranscriptionally that define the response of cells to stimuli. For instance, alternative splicing, posttrans-lational modifications, regulation of enzyme activities, distribution of metabolites between cellular compartments, necessitate analysis at the level of the proteome and the metabolome. 

Sample surface containing both micro-contact-printed banana slice and spot with adsorbed tyrosinase side by side was imaged using the three SECM strategies. The result showed that SECM can be used for detecting enzyme activity distribution in micro-contact-printed samples, and for smdying the changes created by different effects. 

Nowadays the one of the leading cause of death in industrial country is Heart Failure (HF). Under the pathological conditions (e.g., Ischemic Heart Disease (IHD)) the changes in the enzymes activity and ultrastructure of tissue were obtained. The behavior of trace elements may reflect the activity of different types of enzymes. Pathological changes affects only small area of tissue, hence the amount of samples is strictly limited. Thereby, nondestructive multielemental method SRXRF allow to perfonu the analysis of mass samples in a few milligrams, to save the samples, to investigate the elemental distribution on the sample area. 

FIGURE 25.8 In yeast, the functional groups and enzyme activities required for fatty acid synthesis are distributed between a and /3 subunits. 

Livingstone DR, SV Farrar (1984) Tissue and subcellular distribution of enzyme activities of mixed-function oxygenase and benzo[a]pyrene metabolism in the common mussel Mytilis edulis L. Sci Tot Environ 39 209-235. 

Poll C, Thiede A, Wermbter N, Sessitsch A, Kandeler E (2003) Micro-scale distribution of microorganisms and microbial enzyme activities in a soil with long-term organic amendment. Eur J Soil Sci 54 715-724... 

There is no information regarding the metabolism of 3,3 -dichlorobenzidine in children. However, N-acetylation (as discussed above) in humans is likely done by one of two families of N-acetyltransferases. One of these families, NAT2, is developmentally regulated (Leeder and Kearns 1997). Some enzyme activity can be detected in the fetus by the end of the first trimester. Almost all infants exhibit the slow acetylator phenotype between birth and 2 months of age. The adult phenotype distribution is reached by the age of 4-6 months, whereas adult activity is found by approximately 1-3 years of age. Also, UDP-glucuronosyltransferase, responsible for the formation of glucuronide conjugates, seems to achieve adult activity by 6-18 months of age (Leeder and Kearns 1997). These data suggest that metabolism of 3,3 -dichlorobenzidine by infants will differ from that in adults in extent, rate, or both. 

Three major polypeptide bands of 72, 68 and 54 kD, all of which cofractionated with the distribution of enzyme activity on RCGS columns, were seen upon reconstitution in all preparations examined to date (Figure 1). Other polypeptides, whose presence and intensity seemed to vary between preparations, were seen at 45, 42 and 30 and 28 kDa. 

One of the best-characterized effectors and second messenger systems is the cAMP cascade that can be either activated or inhibited by neurotransmit-ter/neuropeptide receptors, including those implicated in anxiety/stress such as CRE Receptors that activate cAMP synthesis couple with the stimulatory G protein, Gsa, and those that inhibit this second messenger couple with the inhibitory G protein, Gia, and these either stimulate or inhibit adenylyl cyclase, the effector enzyme responsible for synthesis of cAMP (Duman and Nestler 1999). There are at least nine different forms of adenylyl cyclase that have been identified by molecular cloning, each with a unique distribution in the brain. The different types of adenylyl cyclase are activated by Gsa as well as the diterpene forskolin, but are differentially regulated by Gia, the Py subunits, Ca, and by phosphorylation. This provides for fine control of adenylyl cyclase enzyme activity and regulation by other effector pathways. 

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