Casein bovine

In order to elucidate relationships between surface active and film forming properties of food proteins, it is useful to examine the surface active properties of proteins whose physical and molecular properties are well characterized e.g. -casein, bovine serum albumin (BSA), lysozyme ( ), and -lactoglobulin (b-Lg) (2jL). These represent a range of tertiary structures for soluble proteins. Lysozyme is a rigid and roughly ellipsoidal molecule, whereas the hydrophobic -casein molecule is mostly a random coil structure. The b-Lg molecule consists almost entirely of antiparallel -sheet strands organized into a flattened cone ( ). 

As already mentioned, dehydroalanine is the postulated reactive precursor for lysinoalanine. Direct evidence for dehydroalanine reactivity was obtained by Friedman et al. (1977). They showed that dehydroalanine derivatives convert lysine side chains in casein, bovine serum albumin, lysozyme, wool, or polylysine to lysinoalanine residues at pH 9 to 10. Related studies showed that protein SH groups generated by reduction of disulfide bonds are completely alkylated at pH 7.6 to lanthionine side chains. These studies demonstrate that lysinoalanine and lanthionine residues can be introduced into a protein under relatively mild conditions, without strong alkaline treatment. They also imply that it should be possible to explore nutritional and toxicological consequences of lysinoalanine and lanthionine consumption in the absence of racemiza-tion (see below). 

Casein (bovine ass) (Some unusual features discussed) 183... 

The main components of the casein fraction in bovine milk are 0(5-caseins. Bovine milk contains phosphoprotein -casein and a52 Casein, both occurring in four genetic variants, identified by the letters A, B, C and D, which differ somewhat in their primary structure. The most common variant is B, which is a polypeptide chain composed of 199 amino acids (molecular weight 23.6 kDa, p/= 4.92-5.35). aj-Caseins comprise from 44 to 55% of the total caseins and ajj-casein comprises approximately 80% of the total aj-caseins. The polypeptide chain contains eight phosphoserine residues located mainly at positions 43-80, which makes this part of the molecule polar. Non-polar side chains of amino adds are located in positions 100-199. ajj-Casein forms insoluble calcium salts in the presence of calcium ions. Fragments of aji-casein are considered to be. X-casein. a52-Casein has a similar structure (molecular weight 25.2 kDa), but is less sensitive to the presence of calcium ions. 

Growth conditions Top,. 37 1 °C (25-47 °C) pHopt. 6.5-7.0, no growth at 4.5-5.0 and 8.0-8.5 Requirements complex biological substances, as casein, bovine serum albumin digest, casein digest, hog gastric mucin or yeast extract ... 

Foam fractionation is a relatively inexpensive technique for protein separation. Most studies in the literature are, however, experimental and very few report on industrial appUcations. Among other appUcations, foam liaclionation has been used to separate wheat flour proteins, ovalbumin, lysozyme, egg albumin, milk proteins (e.g., beta-casein, bovine lactoferrin, bovine serum albumin, alpha-lactalbumin, and beta-lactoglobulin) and potato protein from potato juice waste water after starch extraction (Weijenberg et al., 1978 Keller et al., 1997 Hossain and Fenton, 1998 Brown et al., 1999 Wang and Liu, 2(X)3 Wang etal., 2009). 

In ancient Rome, and especially shown at the construction of the Porta Nigra in Trier, where it was targeted to improve the toughness of adhesive properties and frost resistance of the mortars, substances of organic origin such as milk, casein, bovine blood, or urine were already added to adhesives (Geiss 2006a). 

Casein (bovine milk) 0.736 87K2, 88F1, 95M1... 

P-Casein bovine milk 200 220 -20 000 -3 OOOsh phosphate, pH 6.8 Also- 0.46 81C5... 

Miguel, M., Contreras, M. M., Redo, 1., and Aleixandre, A. (2009). ACE-inhibitory and antihjqjertensive properties of a bovine casein hydrolysate. Food Ghent. 112, 211-214. 

Caseins are the major proteins in bovine milk and about 95% of the caseins exist as casein micelles. The structure and properties of casein micelles influence a wide range of technological uses of milk. Light microscopy, SEM, and TEM have been frequently used to study casein... 

Fig. 9. Backscattered Raman and ROA spectra of the natively unfolded proteins bovine /1-casein (top pair) and human y-synuclein (middle pair) in aqueous buffer at pH 7.0, and of the human tau 46 P301L mutant at pH 4.3. 

The reason that the caseins, which constitute nearly 80% of bovine milk, are unfolded in their native states appears to be to facilitate digestion, since the open rheomorphic structures allow rapid and extensive degradation to smaller peptides by proteolytic enzymes. The natively unfolded structures of many cereal proteins may serve an analogous purpose since they provide nutrition for seedlings. The physiological function of the synucleins in the brain is as yet unclear, but tau is known to promote and stabilize the assembly of microtubules. 

Besides the previously mentioned collagen, a wide variety of natural polymers have been involved in the synthesis of bio-nanohybrid materials with potential application in bone repair and dental prostheses. For instance, some recent examples refer to bionanocomposites based on the combination of HAP with alginate [96,97], chitosan [98,99], bovine serum albumin (BSA) [100], sodium caseinate [101], hyaluronic acid [102], silk fibroin [103,104], silk sericin [105], or polylactic add (PLA) [106,107]. These examples illustrate the increasing interest in the subject of HAP-based biohybrid materials, which has led to almost 400 articles appeared in scientific journals in 2006 alone. 

Hopwood, D. (1969) Comparison of the cross-linking abilities of glutaraldehyde, formaldehyde, and a-hydroxyadipaldehyde with bovine serum albumin and casein. Histochemie 17, 151. 

South Uist in the Outer Hebrides. A number of positive results were obtained and these compared well with the analysis of the fatty acids. However, some samples gave a negative result for ocsl-casein but a positive one for milk fat based on the A13C value. The possibility exists that some of the residues represent sheep milk (which would give a negative result for bovine asi-casein), or that in some cases the casein molecule is degraded with consequent depletion of the immunological response. 

Chemical reactions Polymerization of casein and whey proteins are due to some kind of chemical reactions. The different proteins as found in the supernatant of milk after precipitation at pH 4.6 are collectively called whey proteins. These globular proteins are more water soluble than caseins and are subject to heat dena-turation. Denaturation increases their water-binding capacity. The principal fractions are P-lactoglobulin, a-lactalbumin, bovine serum albumin (BSA), and immunoglobulins (Ig). 

Mostly bovine serum albumin (BSA) is used. Gelatin from cold fish, inactivated calf serum, casein hydrolysate, non-fat dry mUk, polyvinylpyrrolidone, or Tween 20 are also suitable. Concentrations from 0.1 to 0.5% (w/v) are sufficient. Casein and mfik are not of first choice if (strept)avidin conjugates are used. 

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