Grey in the core of each hair. Melanin is also responsible for the color of the skin and of the eyes. There are only two types of pigment: dark (eumelanin) or light (phaeomelanin). Combined in various combinations, these pigments create all natural hair colors. Melanin itself is the product of a specialized cell, the melanocyte, which is found in each hair follicle, from which the hair grows. As hair grows, the melanocyte injects melanin into the hair cells, which contain the protein keratin and which makes up our hair, skin, and nails. As long as the melanocytes continue injecting melanin into
Protein A due to the high purity and yield which are achieved in a easily and reliably achieved. This forms the basis for a general antibody purification "platform" which simplifies manufacturing operations and reduces the time and effort required to develop purification processes. A typical mAb purification process is shown at right. Albeit the long history of protein A chromatography for the production of antibodies, the process is still being improved today. Continuous chromatography, more precisely periodic counter-current chromatography, enormously increases the productivity of the purification step. Protein A Protein A is a 42 kDa surface protein originally found in the cell