GORDON D F, SPECK M L
Appl Microbiol. 1965 Jul;13(4):537-42. doi: 10.1128/am.13.4.537-542.1965.
Certain cultures of Streptococcus cremoris produced a bitter taste that occurred in the whey portion of milk cultures. Whey from a culture which produced bitterness was fractionated on Sephadex. The fraction in which the bitter taste was concentrated was chromatographed successively on paper with butanol-acetic acid-water (5:1:4), and then butanol-2-butanone-water (2:2:1). In each instance, the bitter component was in the most rapidly moving band that gave a positive ninhydrin test. The bitterness was observed to be caused by a peptide containing the following numbers of each amino acid: arginine, 1; glutamic acid, 2; glycine, 2; isoleucine, 2; leucine, 2; phenylalanine, 1; proline, 5; and valine, 4. N-terminal amino acids could be detected by coupling with 2,4-dinitrofluorobenzene or phenylisothiocyanate, or by hydrolysis with leucine aminopeptidase. When treated with carboxypeptidase, only leucine and valine appeared at the C-terminal end, and these were detected simultaneously.
某些乳脂链球菌培养物会产生一种苦味，这种苦味出现在牛奶培养物的乳清部分。将产生苦味的培养物的乳清在葡聚糖凝胶上进行分级分离。将浓缩有苦味的级分先后用正丁醇 - 乙酸 - 水（5:1:4），然后用正丁醇 - 2 - 丁酮 - 水（2:2:1）在纸上进行色谱分析。在每种情况下，苦味成分都在茚三酮试验呈阳性的移动最快的条带中。观察到苦味是由一种含有以下数量各氨基酸的肽引起的：精氨酸1个；谷氨酸2个；甘氨酸2个；异亮氨酸2个；亮氨酸2个；苯丙氨酸1个；脯氨酸5个；缬氨酸4个。N - 末端氨基酸可以通过与2,4 - 二硝基氟苯或苯异硫氰酸酯偶联，或用亮氨酸氨肽酶水解来检测。用羧肽酶处理时，只有亮氨酸和缬氨酸出现在C - 末端，并且是同时检测到的。
