Park C S, Chandler P T
J Dairy Sci. 1976 Feb;59(2):216-23. doi: 10.3168/jds.S0022-0302(76)84187-2.
Effect of labeled precursor amino acids, varying cell densities, graded quantities of amino acid complement, and incubation environment on milk protein synthesis were studied with cultures of mammary cells isolated from Sprague Dawley rats. The essential amino acid complement of Eagle's minimal essential medium was used as base. Protein synthesis, measured by incorporation of labeled lysine, leucine, and phenylalanine, was affected by source of label for the "beta-lactoglobulin fraction" and beta-casein but not alpha-lactalbumin. Cell numbers between 6 X 106 and 6 X 107 per 5 ml of culture medium did not significantly alter rates of synthesis. Increasing amounts of amino acid concentration from one to three-fold increased synthesis of "beta-lactoglobulin fraction" and alpha-lactalbumin regardless of cell population. Response to addition of essential amino acid for "beta-lactoglobulin fraction" synthesis was linear over one to five-fold with 30.9 mug/flask per fold addition (linear regression coefficient; squared correlation = .91). Results were similar for beta-casein synthesis; 25.9 mug/flask and squared correlation = .91. No culturing effects between carbon dioxide and conventional incubators were significant.
利用从斯普拉格-道利大鼠分离的乳腺细胞培养物，研究了标记前体氨基酸、不同细胞密度、分级氨基酸补充量以及培养环境对乳蛋白合成的影响。以伊格尔氏最低必需培养基的必需氨基酸补充物作为基础。通过标记赖氨酸、亮氨酸和苯丙氨酸的掺入来测量蛋白质合成，结果表明，“β-乳球蛋白组分”和β-酪蛋白的蛋白质合成受标记来源的影响，但α-乳白蛋白不受影响。每5毫升培养基中细胞数量在6×10⁶至6×10⁷之间时，合成速率没有显著变化。氨基酸浓度从一倍增加到三倍，无论细胞数量如何，“β-乳球蛋白组分”和α-乳白蛋白的合成都会增加。对于“β-乳球蛋白组分”的合成，添加必需氨基酸的反应在一倍至五倍范围内呈线性，每增加一倍添加30.9微克/瓶（线性回归系数；平方相关系数=0.91）。β-酪蛋白合成的结果相似；每瓶25.9微克，平方相关系数=0.91。二氧化碳培养箱和传统培养箱之间的培养效果没有显著差异。
