Complex Acylation of Angiotensin II by N-Hydroxysulfosuccinimide linked Biotin ReagentsQinfeng Liu*, Andres Lam and Achyut Kathuria
College of Pharmacy and Health Sciences, Campbell University, Buies Creek, NC 27506, USA
- *Corresponding Author:
- Qinfeng Liu
College of Pharmacy and Health Sciences
Campbell University, Buies Creek, NC 27506, USA
E-mail: [email protected]
Received date: December 03, 2015; Accepted date: January 29, 2016; Published date: February 10, 2016
Citation: Liu Q, Lam A, Kathuria A (2016) Complex Acylation of Angiotensin II by N-Hydroxysulfosuccinimide linked Biotin Reagents. J Biomol Res Ther 5:138. doi:10.4172/2167-7956.1000138
Copyright: © 2016 Liu Q, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
N-Hydroxysulfosuccinimide-linked biotins (sulfoNHS-biotins) are water soluble biotin tags commonly used to conjugate a biotin moiety to proteins by rapid N-acylation of primary amines. Unexpected O-acylation by sulfoNHSbiotin on tyrosine of Angiotensin II (Ag-II) and an acylation on third site unable to characterize were identified by LC-MS in addition to the expected N-acylation on the N-terminal of Ag-II. The N-acylation only undergoes incomplete hydrolysis in 0.1% formic acid not at pH 7.2 and 8.0, while two unexpected acylation hydrolyze at both conditions, but their hydrolysis in 0.1% formic acid was much more rapid. Dithiothreitol treatment selectively catalyzed hydrolysis of both of the unexpected acylation but not the N-acylation of Ag-II. The maximum yield of O-acylation of the Ag- II tyrosine was 99% at pH 7.2 and 95% at pH 8.0 as compared N-acylation of lysine when reacted with excess sulfoNHS-biotin with these yields of 94% at pH 7.2 and 96% at pH 8.0. Acylation of the third uncharacterized site of Ag-II showed maximum yield of approximately 17% at pH 7.2, but higher yield (≥ 47%) at pH 8.0 within 30 min. The unexpected O-acylation of the Ag-II tyrosine occurred within 1 min at either pH 7.2 or pH 8.0, as rapidly as the N-acylation, while the other unexpected acylation required more time to complete at pH 8.0.