환원탈지유배지에서 자란 Lactobacillus helveticus YM-1의 cell-free filtrate로부터 Streptococcus thermophilus CH-1의 생육촉진을 확인한 결과 이 물질은 분자량이 5,000정도의 peptide로 나타난다. 이 peptide 중에는 aspartic acid, Iysine, proline, leucine, valine, alanine, glutamic acid등의 amino산이 비교적 풍부하였으며, 그중에서 glutamic acid 함량이 가장 높았다. 또 이 Peptide가 생육 촉진효과 나타내는데 가장 중요한 역할을 담당하는 것은 glutamic acid와 Phenylalanine으로 판단되었다.
A compound stimulatory to the growth of S. thermophilus CH-1 was isolated from the cell-free filtrate of L. helveticus YM-1 in milk medium. The stimulant was identified as a peptide with a molecular weight of approximately 5000 and exhibited positive ninhydrin reaction. Some kinds of amino acids confirmed as aspartic acid, alanine, valine, glutamic acid, lysine, proline, leucine were rich in the stimulatory peptide hydrolysate. Among them, glutamic acid was most abundant. Judging from bioautographic results, glutamic acid and phenylalanine were expected to exert an important role for the stimulation.
