Elastin physical properties

A star copolymer (SCP) of PCLA was synthesized by Younes and coworkers. This kind of SCP PCLA elastomer was also synthesized in two steps. First, the small molecular SCP was produced by ring-opening polymerization of s-caprolactone (s-CL) with glycerol as initiator and stannous 2-ethyUiexanoate as catalyst. Second, the living SCP was further reacted with different ratios of a cross-linking monomer, such as 2,2-bis(s-CL-4-yl)-propane (BCP) and s-CL. The SCP elastomers had very low glass transition temperature (—32°C). It was reported that the SCPs were soft and weak with physical properties similar to those of natural bioelastomers such as elastin. A logarithmic decrease in each tensile property with time was observed in this SCP PCLA. 

Resilin and elastin, unlike other structural proteins, fulfill both definitions of an elastic material. Colloquially speaking, resilin and elastin are stretchy or flexible. They also fulfill the strict definition of an elastic material, i.e., the ability to deform in proportion to the magnitude of an applied stress without a loss of energy, and the recovery of the material to its original state when that stress is removed. Resilin and elastin are alone in the category of structural proteins (e.g., collagen, silk, etc.) in that they have the correct blend of physical properties that allow the proteins to fulfill both definitions of elasticity. Both proteins have high extensibility and combine that property with remarkable resilience [208]. 

This enzyme catalyzes the hydrolysis of proteins, including elastin, with preferential cleavage at Ala-Xaa. The following are reviews on the molecular and physical properties of this enzyme [EC 3.4.21.36 (pancreatic) and EC 3.4.21.37 (leukocyte)]. 

The final analyses of the three elastin preparations are so similar that it is tempting to regard the proteins as identical and to ascribe the small differences as due to the presence of resistant impurities. That there are real differences between the elastins of different tissues can be shown by an examination of the physical properties of the different products. Slight differences in staining reactions have already been noted, but recent work in this laboratory has shown that there are marked differences in the rate of alkaline hydrolysis between the different samples. Figure 3 shows the... 

Basically, there are three major groups of proteins in muscle tissue (a) the sarcoplasmic proteins of the muscle cell cytoplasm, (b) the myofibrillar proteins, soluble at high ionic strengths, that make up the myofibril or contractile part of the muscle, and (c) the stromal proteins comprised largely of the connective tissue proteins, collagen, and elastin. The myofibrillar proteins and the stromal proteins are fibrous and elongated they form viscous solutions with large shear resistance. These properties coupled with other lines of indirect evidence indicate that the physical properties of the myofibrillar and stromal proteins are directly related to the texture and tenderness of meat (34). 

The synthesis of well-defined macromolecular structures with controlled properties is critical for the production of advanced materials for biological and industrial applications. Inspired by nature s ability to create proteins with exquisite control, we focus on the applications of elastin and elastin-derived polymers for materials design. The elucidation of elastin biochemical, conformational and physical properties offers insight into the fabrication of novel biomaterials. As part of this review, we highlight some of the recent advances that permit the generation of customized elastin-based polymers. These developments provide an added level of control vital to the future construction of tailor-made supramolecular structures with emergent physical, mechanical and biological properties. 

The precise understanding of the structural nature of elastin remains elusive because the unusual physical properties of native elastin have prevented the use of traditional structural biology techniques. The hydrophobic domains are dominated by a pentapeptide repeat sequence of (Val-Pro-Gly-Val-Gly). This repeat sequence is believed to endow elastin its remarkable elastic properties, allowing continual expansion and contractions without loss of structural integrity (2). 

Table 7. Physical properties of the synthetic poly(W4) from human elastin. " ...

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