Property patterns were constructed, based on an alignment of related domains in human complement subcomponents C1r and C1s as well as in the sea urchin protein uEGF. This kind of consensus pattern was able to identify similar domains in a human bone morphogenic protein, in a Xenopus laevis embryonal protein involved in dorsoanterior development and in a calcium-dependent serine protease secreted from malignant hamster embryo fibroblast cells. Because of the high level of overall sequence homology this protease may be the hamsters' equivalent of the human complement subcomponent C1s. The resulting multiple alignment of all studied domains suggests functionally and structurally important regions.