Elongation repetition

The periodic phenomenon described above indicates that the entire channel acts like the area beneath a growing bubble, going through periodic drying and rewetting. The cycle was repetitive with venting of the elongated bubble. Such a behavior affects the mean flow characteristics that usually are measured at the manifolds. 

The biosynthesis of polyketides (including chain initiation, elongation, and termination processes) is catalyzed by large multi-enzyme complexes called polyketide synthases (PKSs). The polyketides are synthesized from starter units such as acetyl-CoA, propionyl-CoA, and other acyl-CoA units. Extender units such as malonyl-CoA and methylmalonyl-CoA are repetitively added via a decarboxylative process to a growing carbon chain. Ultimately, the polyketide chain is released from the PKS by cleavage of the thioester, usually accompanied by chain cyclization [49]. 

Elongation is the repetitive addition reactions of actin-ATP (Fig. 2). The actin-bound ATP is hydrolyzed during/after monomer addition to filaments, forming polymer-bound ADP and releasing orthophosphate. The kinetics of elongation conform to that predicted by the following rate law ... 

At the conclusion of the initiation process, the ribosome is poised to translate the reading frame associated with the initiator codon. The translation of the contiguous codons in mRNA is accomplished by the sequential repetition of three reactions with each amino acid. These three reactions of elongation are similar in both prokaryotic and eukaryotic systems two of them require nonribosomal proteins known as elongation factors (EF). Interestingly, the actual formation of the peptide bond does not require a factor and is the only reaction of protein synthesis catalyzed by the ribosome itself. 

Fibrous protein sequences are often characterized by the presence of simple repetitive motifs. Some are exact in length and/or sequence, but others are only approximate and display considerable variation. Some motifs contain residues that are absolutely conserved in some positions, whereas in others it is only the sequence character that is maintained over the repeat length. In many fibrous proteins the repeats occur contiguously, whereas in others they are found widely separated in the sequence. The varieties of sequence repeat that have been observed are typed and catalogued here by Parry (Chapter 2). Each motif forms a discrete element of structure in many instances, these are arranged helically with respect to one another. In many cases an elongate structure is formed, and this can lead naturally to molecular aggregation and the formation of functional filaments. 

---