Promoters 3-lactalbumin

There are a number of media available which are not based on a detailed investigation of growth requirements, but rather include crude mixtures of nutrients added to promote cell growth. These include lactalbumin hydrolysate (Appendix 1 Table 9) or yeast extract (Appendix 4) to provide an inexpensive source of amino acids or vitamins. Thus Melnick s monkey kidney media A and B (Melnick, 1955) contain lactalbumin hydrolysate and calf serum in Hanks and Earle s BSS, respectively. Chick embryo extract and tryptose phosphate broth (Appendix 1, Tables 11 and 12) are also used occasionally and their use is referred to where appropriate throughout the book. Mitsuhashi and Maramorosch mosquito cell medium contains lactalbumin hydrolysate, yeast extract and foetal calf serum in a specially developed saline (Mitsuhashi and Maramorosch, 1964 Singh, 1967). 

In addition to high pH, increases in the length of treatment and Increases in temperature are factors which promote increased racemization. Friedman, et al. (61) have shown that for casein, half of the amount of aspartic acid that will racemize within 24 hours (at 65 C in O.lN NaOH) will do so within the first hour. Others have shown similar results for proteins such as soy isolate and lactalbumin, with 60% to 80% racemization occurring with the first hour at 100 C (O.lN NaOH)( ). 

Pure oil/protein solution systems The Interfacial Displacement Tensiometer was used to examine the effect of additives known to promote an appreciable interfacial rheology. The systems selected were Toluene/a-lactalbumin (100 ppm), toluene/BSA (100 ppm), and nonane/BSA (100 ppm) these systems were expected to produce highly visco-elastic interfacial films. The BSA solution when displaced by either toluene or nonane (see Figure 11) gave rise to pressure jumps on the I.D.T. traces at points equivalent to entry and exit of the narrower capillary. These peaks indicate an increased resistance to displacement of the interface associated with its deformation and changes of extent. The maximum pressures are considerably in excess of those given by the pure oil/water reference system, also shown in Figure 11. 

D-Galactosyltransferases.—The D-galactosyltransferase associated with the lactose synthase system in cows milk exists as a monomer (mol. wt. 4.6 x 10 ), although its aggregation is promoted by 2-acetamido-2-deoxy-D-glucose. Complexation of the enzyme with a-lactalbumin was investigated. 

The issue of bioavailability from food sources and the interactions between food groups and copper availability remains a critical question. Lonnerdal et al. demonstrated that heat treatment of cows milk formula decreases the copper bioavailability. Transitional complexes form in the milk upon heating that have a similar configuration to copper and thereby directly inhibit copper absorption. High doses of zinc also reduce copper bioavailability, as does combined iron and zinc supplementation. The dilemma is how to prepare an infant formula containing adequate copper, iron, and zinc that will meet the RDA for copper. Other nutrients dramatically affect copper absorption from foods. Soy protein-based diets promote less copper retention in tissues than lactalbumin-based diets. However, it is unclear if this effect is solely due to the soy protein composition or to the higher zinc in these soy-based formulas. In animals, phytate causes a drop in serum copper but human stable isotope studies reveal no... 

---