Abstract
The membrane protein profiles of marine budding bacteria belonging to the genus Hyphomonas were determined and analyzed. Hyphomonas spp. synthesized an unusually large number (four or more) of high-apparent-molecular-weight proteins (apparent molecular weight, .gtoreq. 64,000). Species were compared by using a membrane protein profile index developed for this study. Our results supported the division of extant members of this genus into five species. The membrane protein profile index for Hyphomonas hirschiana and Hyphomonas neptunium was higher than suggested by other phenetic characteristics.