Maturation processes

Because the metaHoporphyrins can provide insights into petroleum maturation processes, they have been studied extensively, and several families of related stmctures have been identified. On the other hand, the bulk of the metals are found in the heaviest fraction. Because those highly polar fractions do... 

Deficiency. Macrocytic anemia, megaloblastic anemia, and neurological symptoms characterize vitamin B 2 deficiency. Alterations in hematopoiesis occur because of the high requirement for vitamin B 2 for normal DNA repHcation necessary to sustain the rapid turnover of the erythrocytes. Abnormal DNA repHcation secondary to vitamin B 2 deficiency produces a defect in the nuclear maturational process of committed hematopoietic stem cells. As a result, the erythrocytes are either morphologically abnormal or die during development. 

Congeners. Congeners are the flavor constituents in beverage spirits that are responsible for its flavor and aroma and that result from the fermentation, distillation, and maturation processes. 

The flavor and aroma of distilled spidts are derived primarily from minor constituents called congeners that are produced and augmented in the fermentation and maturation processes. The congener profiles for various distilled spidts are shown in Table 2. 

Alcohohc beverages are made up primarily of ethanol, congeners, and water. Congeners are vaporized with the alcohol in distillation below 190° proof and are developed during the maturation process by oxidation and other reactions. These components contribute to palatability and create the characteristic appearance, aroma, and taste of a particular spidt. When the spirit is distilled at a lower proof, more congeners are present and the spirits possess more character. Congeners are usually reported either as grams per 100 Hters at "as is" proof, or as 100° proof at parts per million or parts per billion. 

Reife-stadium, n. stage of maturity, -vorgang, m. ripening or maturing process, -zustand, m. ripe state, ripeness. 

After their synthesis (translation), most proteins go through a maturation process, called post-translational modification that affects their activity. One common post-translational modification of proteins is phosphorylation. Two functional classes of enzymes mediate this reversible process protein kinases add phosphate groups to hydroxyl groups of serine, threonine and tyrosine in their substrate, while protein phosphatases remove phosphate groups. The phosphate-linking... 

Terminase inhibition is an antiviral approach that may also be of consequence for other members of the herpesvirus group. In addition, since a similar DNA maturation process does not occur in higher cells, this principle offers the potential for high selectivity, in contrast to many of the viral DNA polymerase inhibitors, which also interact with cellular enzymes and hence can have severe side effects. 

A completely distinct enzyme has been found in a number of organisms, which carry out the metabolism of amino acids. In this group, a pyruvoyl group is covalently bound to the active enzyme that is produced from a proenzyme in a self-maturation process (Toms et al. 2004). The proenzyme contains a serine residue that undergoes rearrangement to an ester followed by conversion into the (3-chain of the enzyme and a dehydroalanine residne that forms the A-terminal pyruvoyl group of the a-chain. This type of enzyme has been fonnd for a number of important decarboxylations ... 

Studies have shown that plants can make biologically active recombinant proteins through both transgenic and transient expression approaches. Although the plant post-translational machinery is similar to that of mammalian cells, there are some notable differences, e.g. differences in glycosylation, particularly the absence of sia-lation, which may impact the activity of certain proteins. The absence of mammalian enzymes may prevent complex maturation processes that are critical for the biological activity of proteins such as insulin. Fortunately these shortcomings affect the activity of only a limited number of proteins. 

As secretory vesicles mature, many secretory polypeptides undergo post-translational modifications. Many hormones and neuropeptides as well as hydrolytic enzymes are synthesized as inactive polypeptide precursors that need to undergo proteolysis to become active. This maturation process usually starts in the TGN and continues in the secretory vesicles, but may be completed in the extracellular space soon after exocytosis takes place in some cases. The maturation process for neuropeptides is described in Chapter 18. 

Adolescence is a time of novelty seeking related to curiosity and learning skills for survival that maybe part of a natural maturation process. Adolescent brains are not fully mature, especially the frontal lobes, which have to do with problem... 

Cast lead-calcium-tin alloys, 14 775 Cast-link belt furnaces, 12 289 Cast-mature process, in bar soap manufacture, 22 749 Cast multicrystalline silicon material, 23 40... 

Transparent soaps, 22 747-748 cast-mature process for, 22 749 Transparent thermal insulation,... 

Despite this, the principle of the fuel cell was not able to be developed into a technically mature process for a long time. The main reasons, apart from insufficient knowledge of the electrochemical processes involved, were material problems. Around the turn of the century, the dynamo generator (1866, Siemens), combustion... 

Figure 4 The biosynthesis of nisin A as a representative example of the posttranslational maturation process of lantibiotics. Following ribosomal synthesis, NisB dehydrates serine and threonine residues in the structural region of the prepeptide NisA. NisC subsequently catalyzes intramolecular addition of cysteine residues onto the dehydro amino acids in a stereo- and regioselective manner. Subsequent transport of the final product across the cell membrane by NisT and proteolytic cleavage of the leader sequence by NisP produces the mature lantibiotic. For the sequence of the leader peptide, see Figure 6. Adapted with permission from J. M. Willey W. A. van der Donk, Annu. Rev. Microbiol. 2007, 61, 477-501.

Of the various MutA leader peptide mutations generated in vivo, only Leu—7Lys and He—4Asp fully disrupted mutacin II biosynthesis, but it could not be determined what step(s) in the overall maturation process had been perturbed. Recent in vitro studies with mutants of LctA at Leu—7 showed that incorporation of any charged residue strongly perturbed lacticin 481 synthetase activity whereas the Leu—7Ala mutant was still... 

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