Lecithin Living

Phosphorus, like nitrogen, is an essential constituent of living matter where it may be partly in combination (as phosphate groups) with organic groups, for example in lecithin and egg yolk, or mainly in inorganic form, as calcium phosphate(V), in bones and teeth. 

Lecithins are essential components of cell membranes and, in principle, may be obtained from a wide variety of living matter. In practice, however, lecithins are usually obtained from vegetable products such as soybean, peanut, cottonseed, sunflower, rapeseed, corn, or groundnut oils. Soybean lecithin is the most commercially important vegetable lecithin. Lecithin... 

This research has been carried out in our laboratory and is still actively pursued— this is part of our enterprise in the direction of the minimal living cell. It is not the aim of this review to dwell upon this part. The interested reader is referred to our work concerned with enzymes in liposomes, in particular to the work dealing with lecithin-producing enzymes in lecithin liposomes, or the following work on enzymatic and molecular biological reaction taking place in vesicles and liposomes. " ... 

The term encapsulation has been used to distinguish entrapment preparations in which the biocatalyst environment is comparable to that of the bulk phase and where there is no covalent attachment of the protein to the containment medium (Fig. 6-1 D)[21J. Enzymes or whole cells may be encapsulated within the interior of a microscopic semi-permeable membranes (microencapsulation) or within the interior of macroscopic hollow-fiber membranes. Liposome encapsulation, a common microscopic encapsulation technique, involves the containment of an enzyme within the interior of a spherical surfactant bilayer, usually based on a phospholipid such as lecithin. The dimensions and shape of the liposome are variable and may consist of multiple amphiphile layers. Processes in which microscopic compart-mentalization (cf. living cells) such as multienzyme systems, charge transfer systems, or processes that require a gradient in concentration have employed liposome encapsulation. This method of immobilization is also commonly used for the delivery of therapeutic proteins. 

Phosphatides that occur in a great variety of vegetables, oil crops, living organisms and egg yolk are well-known natural zwitter-ionic surfactants. Their complex mixtures are known also as "lecithin". The lecithin constituents can be illustrated by phospholipids and sphingolipids as exemplified by a-phosphatidylcholine (A) and sphingomyelin (B), respectively ... 

The literature for peptide-membrane interactions is both vast and well covered. For the purposes of this chapter, we will look only at polymers - molecules made from polymerization reactions rather than solid-state synthesis or extracted from living organisms - made from a- and p-amino acids. Yaroslavov et al examined binding between poly-a-r-lysine (PLL) and anionic vesicles. SUVs of lecithin and cardiolipin were labeled with pyrene and exposed to PLL (Cl6) (Figure 21). The decrease in pyrene fluorescence indicated that PLL binds to the vesicles. Saturable binding was observed. The addition of high concentrations of salt or low... 

It turned out to be true that proteinoids, without any lipids, also form bimolecular membranes.Despite the fact that black proteinoid membranes are not as long-lived in the ultrathin state as phospholipid membranes, they last long enough to be examined. Those rich in hydrocarbon-rich amino acid side chains mostly display properties characteristic for BLMs. The same polymers are among those that most readily combine with lecithin. 

CH2OHCH2N(CH3)30H. It occurs widely in living organisms as a constituent of certain types of phospholipids - the lecithins and sphingomyelins - and in the neuro transmitter acetjdcholine. It is sometimes classified as a member of the vitamin B complex. 

The different varieties of orthophosphoric monoesters and diesters which are present in all living species are exceedingly numerous. Biologically important monoesters include the mononucleotides such as, for example, adenylic acid (adenosine monophosphate, AMP), inosinic acid, vitamin Bg and many phosphorylated proteins, for example, milk caseins. Biologically important diesters include the phospholipids (e.g. lecithin and phosphatidyl inositol), plasmalogens, sphingomyelins, cyclic nucleotide monophosphates (e.g. cyclic AMP), some teichoic acids, vitamin Bj2 and of course the immensely important nucleic acids (polynucleotides) (Chapters 10 and 11). The great stability of diesters is an essential feature of the chemistry of polynucleotides. 

Living matter only synthesizes a-lecithins which are to be found in all cells. The existence of so many a-lecithins is due to the diversity of the groups Rx and R which imiy be saturated or unsaturated. Choline, the base present in lecithin, is also widely distributed in the biosphere ... 

A versatile phospholipid found in all living organisms. It is a mixture of the diglycerides of the fatty acids stearic, palmitic, and oleic combined with the choline ester of phosphoric acid. The body is capable of synthesizing lecithin. In addition, lecithin is found in a wide variety of foods. At this time, there is no evidence that lecithin has any nutritional significance. 

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