Enzyme to proteins

Avrameas, S. (1969) Coupling of enzyme to proteins with glutaraldehyde. Immunochemistry 6, 43-52. 

Avremeas S. Coupling of enzymes to proteins with glutaraldehyde use of the conjugates for the detection of antigens and antibodies. Immunohistochemistry 1971 6 394. 

Mihalyi, E., Application of Proteolytic Enzymes to Protein Structure... 

Conjugation of enzyme to protein A or IgG using A-succinimidyl-3-(2-pyridyldithio)-... 

This paper reviews the effects of enzymes on the functional properties of proteins, protein concentrates, and protein isolates. In addition, selected food systems are discussed to relate the action of endogenous and exogenous enzymes to protein functionality in the food. 

The myofibrillar proteins of fish are those proteins soluble in 0.6M NaCl (14). These proteins have been modified with Rhozyme P-11 at an enzyme-to-protein ratio of 1 75 at 30 °C, pH 6.6 for 1 hr. The modified myofibrillar protein was quantitatively recovered as a hexametaphosphate complex at pH 3. Residual lipids were removed by solvent extraction of the complex. After a solution of the phosphate-protein complex was neutralized to pH 7, it was spray-dried or freeze-dried to yield a freely soluble product which was 93.5% protein, 0.15% lipid, and 1.4% phosphate. 

Mihalyi, E. (1978) Proteolytic enzymes, enzymatic proteolysis—general considerations, in Application of Proteolytic Enzymes to Protein Structure Studies, 2nd ed., 1,43-149... 

Most reactions in cells are carried out by enzymes [1], In many instances the rates of enzyme-catalysed reactions are enhanced by a factor of a million. A significantly large fraction of all known enzymes are proteins which are made from twenty naturally occurring amino acids. The amino acids are linked by peptide bonds to fonn polypeptide chains. The primary sequence of a protein specifies the linear order in which the amino acids are linked. To carry out the catalytic activity the linear sequence has to fold to a well defined tliree-dimensional (3D) stmcture. In cells only a relatively small fraction of proteins require assistance from chaperones (helper proteins) [2]. Even in the complicated cellular environment most proteins fold spontaneously upon synthesis. The detennination of the 3D folded stmcture from the one-dimensional primary sequence is the most popular protein folding problem. 

Calculation of Conformational Free Energies for a Model of a Bilobal Enzyme Protein kinases catalyze the transfer of phosphate from adenosine triphosphate (ATP) to protein substrates and are regulatory elements of most known pathways of signal transduction. 

The most striking thing about proteins is the diversity of their roles m living sys terns siUc is a protein skin and hair are mostly proteins many hormones are proteins a protein carries oxygen from the lungs to the tissues where it is stored by another pro tern and all enzymes are proteins... 

Once the broad outlines of DNA replication and protein biosynthesis were established scien tists speculated about how these outlines af fected various origins of life scenarios A key question concerned the fact that proteins are re quired for the synthesis of DNA yet the synthesis of these proteins is coded for by DNA Which came first DNA or proteins How could DNA store genetic infor mation if there were no enzymes to catalyze the polymerization of its nucleotide components How could there be proteins if there were no DNA to code for them ... 

Hydrolyzed Vegetable Protein. To modify functional properties, vegetable proteins such as those derived from soybean and other oil seeds can be hydrolyzed by acids or enzymes to yield hydrolyzed vegetable proteins (HVP). Hydrolysis of peptide bonds by acids or proteolytic enzymes yields lower molecular weight products useful as food flavorings. However, the protein functionaHties of these hydrolysates may be reduced over those of untreated protein. 

Plasteins ate formed from soy protein hydrolysates with a variety of microbial proteases (149). Preferred conditions for hydrolysis and synthesis ate obtained with an enzyme-to-substrate ratio of 1 100, and a temperature of 37°C for 24—72 h. A substrate concentration of 30 wt %, 80% hydrolyzed, gives an 80% net yield of plastein from the synthesis reaction. However, these results ate based on a 1% protein solution used in the hydrolysis step this would be too low for an economical process (see Microbial transformations). 

Metabolic Functions. The functions of the thyroid hormones and thus of iodine are control of energy transductions (121). These hormones increase oxygen consumption and basal metaboHc rate by accelerating reactions in nearly all cells of the body. A part of this effect is attributed to increase in activity of many enzymes. Additionally, protein synthesis is affected by the thyroid hormones (121,122). 

Erythrocyte Entrapment of Enzymes. Erythrocytes have been used as carriers for therapeutic enzymes in the treatment of inborn errors (249). Exogenous enzymes encapsulated in erythrocytes may be useful both for dehvery of a given enzyme to the site of its intended function and for the degradation of pathologically elevated, diffusible substances in the plasma. In the use of this approach, it is important to determine that the enzyme is completely internalized without adsorption to the erythrocyte membrane. Since exposed protein on the erythrocyte surface may ehcit an immune response following repeated sensitization with enzyme loaded erythrocytes, an immunologic assessment of each potential system in animal models is required prior to human trials (250). 

The numerous separations reported in the literature include surfactants, inorganic ions, enzymes, other proteins, other organics, biological cells, and various other particles and substances. The scale of the systems ranges from the simple Grits test for the presence of surfactants in water, which has been shown to operate by virtue of transient foam fractionation [Lemlich, J. Colloid Interface Sci., 37, 497 (1971)], to the natural adsubble processes that occur on a grand scale in the ocean [Wallace and Duce, Deep Sea Res., 25, 827 (1978)]. For further information see the reviews cited earlier. 

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