当前位置： SCI文献检索 > BIOCHEMISTRY期刊下所有文献 > Patterns of proteolytic cleavage and carbodiimide derivatization in sarcoplasmic reticulum adenosinetriphosphatase.

Patterns of proteolytic cleavage and carbodiimide derivatization in sarcoplasmic reticulum adenosinetriphosphatase.

Abstract：

:Two series of experiments were carried out to characterize (a) peptide fragments of sarcoplasmic reticulum (SR) ATPase, based on proteolysis with different enzymes and distribution of known labels, and (b) specific labeling and functional inactivation patterns, following ATPase derivatization with dicyclohexylcarbodiimide (DCCD) under various conditions. Digestion with trypsin or chymotrypsin results in the initial cleavage of the SR ATPase in two fragments of similar size and then into smaller fragments, while subtilisin and thermolysin immediately yield smaller fragments. Peptide fragments were assigned to segments of the protein primary structure and to functionally relevant domains, such as those containing the 32P at the active site and the fluorescein isothiocyanate at the nucleotide site. ATPase derivatization with [14C]DCCD under mild conditions produced selective inhibition of ATPase hydrolytic catalysis (EP + H2O in equilibrium E + Pi) without significant incorporation of the 14C radioactive label. This effect is attributed to blockage of catalytically active residues by reaction of the initial DCCD adduct with endogenous or exogenous nucleophiles. ATPase derivatization with [14C]DCCD under more drastic conditions produced inhibition of calcium binding, 14C radioactive labeling of tryptic fragments A1 and A2 (but not of B), and extensive cross-linking. Intermolecular and, to some extent, intramolecular cross-linking were prevented by exogenous nucleophiles. The presence of calcium during derivatization prevented functional inactivation, radioactive labeling of fragment A2, and internal cross-linking of fragment A1. It is proposed that both A1 and A2 fragments participate in formation of the calcium binding domain and that the labeled residues of fragment A2 are directly involved in calcium complexation.(ABSTRACT TRUNCATED AT 250 WORDS)

journal_name

Biochemistry

journal_title

Biochemistry

authors

de Ancos JG,Inesi G

doi

10.1021/bi00405a061

subject

Has Abstract

pub_date

1988-03-08 00:00:00

pages

1793-803

issue

eissn

0006-2960

issn

1520-4995

journal_volume

pub_type

杂志文章

在线工具

Patterns of proteolytic cleavage and carbodiimide derivatization in sarcoplasmic reticulum adenosinetriphosphatase.