Amino Acids of the Shope Papilloma Virus

Abstract

Discussion and Summary The results of the amino acid analyses indicated that at least 18 amino acids are represented in the protein of the Shope papilloma virus. None of these appear to be present in extraordinary amounts. In common with other viruses examined thus far(⁹,¹³,¹⁴), the protein of the papilloma virus has a preponderance of acidic amino acids over the basic ones, and hence differs from the proteins combined with nucleic acid in such substances as sperm. A summation of the amino acid residues and the nucleic acid in the papilloma virus leaves about 7% of the material unaccounted for. However, the nucleic acid figure taken from the data of Taylor et al.(⁷) is admittedly a crude estimate and, as judged from the phosphorus content of his preparations, is almost surely low. Further investigation of the nucleic acid content together with additional amino acid analyses may resolve the discrepancy, but at present the possible existence in papilloma virus preparations of material in addition to protein and nucleic acid cannot be excluded with the same degree of assurance as in the case of certain plant viruses. Finally, the amino acid values reported here must be considered subject to revision owing to the small number of analyses made.