title: Thymosin alpha 1 is a native peptide in several tissues.
abstract: Failure to detect thymosin alpha 1 (T alpha 1) in tissue extracts prepared by procedures that prevent proteolytic activity has hitherto supported the suggestion that T alpha 1 is not a natural peptide, but the product of uncontrolled proteolysis of prothymosin alpha (ProT alpha), a polypeptide that includes T alpha 1 at its NH2 terminus. In this work, purification by isoelectric focusing of a product with the same isoelectric point as synthetic T alpha 1, and its further characterization, demonstrated that T alpha 1 is present as a native peptide in calf thymus and in several lymphoid and non-lymphoid rat tissues. T alpha 1 shows abnormal chromatographic behaviour which appears to be due to association with other components in tissue extracts. In all the tissues studied, T alpha 1 was present in higher concentration than ProT alpha (80-183 and 44-123 micrograms per gram of tissue, respectively). The ProT alpha/T alpha 1 ratio did not change when no measures were taken to prevent proteolysis during tissue homogenization.
authors.affiliation: Departamento de Bioquímica e Bioloxía Molecular, Facultade de Bioloxía, Universidade de Santiago de Compostela, Spain.
authors.forename: F J
authors.initials: FJ
authors.lastname: Franco
authors.forename: C
authors.initials: C
authors.lastname: Diaz
authors.forename: M
authors.initials: M
authors.lastname: Barcia
authors.forename: M
authors.initials: M
authors.lastname: Freire
mesh_terms: D000818:Animals; D002417:Cattle; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D007525:Isoelectric Focusing; D008221:Lymphoid Tissue / Q000737:chemistry*; D011498:Protein Precursors / Q000302:isolation & purification* / Q000378:metabolism; D051381:Rats; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000378:metabolism; D013950:Thymus Gland / Q000737:chemistry*; D014020:Tissue Extracts / Q000737:chemistry
chemical_list: D011498:Protein Precursors; D014020:Tissue Extracts; C040782:prothymosin alpha; D013947:Thymosin; D000077596:Thymalfasin