期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1983
卷号：80
期号：3
页码：765-769
DOI：10.1073/pnas.80.3.765
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Connective tissue activating peptides (CTAPs) extracted from leukocytes and platelets stimulate glycolysis and synthesis of glycosaminoglycan and DNA in cultured human connective tissue cells. CTAP-III, isolated from fresh or outdated human platelets, is a low molecular weight single-chain protein with an isoelectric point of 8.5 that markedly stimulates DNA synthesis and multiple aspects of glycosaminoglycan and proteoglycan metabolism. This report presents a definitive comparison of CTAP-III prepared by two methods [one designated (A), alternative] with similar platelet proteins described by others, beta-thromboglobulin (beta-TG) and low-affinity platelet factor 4 (LA-PF-4). CTAP-III, CTAP-III(A), LA-PF-4, and beta-TG have common antigenic determinants documented by immunoprecipitation and radioimmunoassay. CTAP-III, CTAP-III(A), and LA-PF-4 are biologically active in that they stimulate DNA and glycosaminoglycan synthesis by human synovial cells; beta-TG is inactive. Carboxyl-terminal digestion gave identical terminal sequences for CTAP-III, CTAP-III(A), and beta-TG. Amino-terminal sequence data indicate that CTAP-III and CTAP-III(A) (also LA-PF-4) are identical and differ from beta-TG only by an additional amino-terminal tetrapeptide (Asn-Leu-Ala-Lys-). The biologically active molecule, CTAP-III, may be proteolytically converted to its inactive degradation product (beta-TG) in the course of platelet aging, platelet storage, release from the platelets, or initiation of biological activity.
