Chemical Composition of a Bacteriophage for Streptococcus diacetilactis

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Abstract
Electron photomicrographs revealed that the tadpole-shaped phage particle had a head width and length of 60 ny and a tail length of about 170 m[mu]. The dried phage contained 4.45% P and 12.8% of the protein was N. Bacteriophages prepared in broth medium were recovered by differential centrifugation and purified in a cesium chloride density gradient. An amino acid analysis revealed the following mole percentages for these acids: lysine, 8.1; histidine, 1.7; arginine, 3. 8; aspartic acid plus asparagine, 10.0; threonine, 7.5; serine, 6.8; glutamic acid plus glutamine, 12.0; proline, 3.4; glysine, 9.0;alanine, 9. 5; valine, 8. 9; methionine, 1.1; isoleucine, 7.9; tyrosine, 2.2 and phenylalanine, 2. 8. The nucleic acid of the phage was double-stranded DNA with a thermal melting point (Tm) of 84. 3 C; from this, an average composition of 35.7% guanine plus cytosine was calculated.