Home
Resources
Publications
Reactivity of Lysyl Residues on the (Ca(2+)-Mg2+)-ATPase to 7-amino-4-methylcoumarin-3-acetic Acid Succinimidyl Ester

Reactivity of Lysyl Residues on the (Ca(2+)-Mg2+)-ATPase to 7-amino-4-methylcoumarin-3-acetic Acid Succinimidyl Ester

H I Stefanova, A M Mata, J M East, M G Gore, A G Lee

Biochemistry. 1993 Jan 12;32(1):356-62.

PMID: 8418855

Abstract:

The (Ca(2+)-Mg2+)-ATPase of sarcoplasmic reticulum was labeled with the succinimidyl ester of 7-amino-4-methylcoumarin-3-acetic (AMCA). Although a large number of residues were labeled, it was found that Lys-492 was labeled preferentially at pH values between 6 and 8, consistent with an unusual environment for this residue. Labeling was reduced in the presence of ATP, suggesting that Lys-492 is in or near the ATP binding site of the ATPase. Other identified residues labeled by AMCA were Lys-35, Lys-135, Lys-218, Lys-371, and Lys-605. It is suggested that these represent surface-exposed lysyl residues. Lys-515, labeled by fluorescein isothiocyanate (FITC), was not labeled by AMCA. Labeling with AMCA at pH 6.0 has no effect on ATPase activity, suggesting that Lys-492 is not essential for activity. The fluorescence of AMCA-labeled ATPase did not change on addition of either ATP in the presence of Ca2+ or Pi in the absence of Ca2+, suggesting that Lys-492 was not affected by any major conformational changes on the ATPase. The efficiency of fluorescence energy transfer between AMCA and FITC labels on the ATPase was unaffected by binding Ca2+ or vanadate, arguing against any large-scale movement of the cytoplasmic domains of the ATPase.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP1234203452	5-Norbornene-2-acetic acid succinimidyl ester		1234203-45-2	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: