title: New preparative schedule and further characterization of a thymocyte specific growth factor from calf thymus.
abstract: Purification of a thymocyte specific growth factor is described. A formic acid extract of calf thymus was acetone precipitated, extracted with acidic methanol and precipitated with ether. With an assay based on the stimulation of DNA synthesis in thymocyte cultures the crude extract was purified by several steps of gel filtration and ion exchange chromatography. The stimulating activity had an apparent Mr of 1,600 and a pI of 5.6-5.9 and was devoid of reactive amino groups. It behaved amphoteric and was sensitive to pronase. We propose that the activity resides in an N-terminal-blocked peptide without biochemical relationship to defined thymic differentiation hormones or established growth factors.
mesh_terms: D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D006133:Growth Substances / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D013950:Thymus Gland / Q000032:analysis*
chemical_list: D006133:Growth Substances