Proteoliposomes with the ability to transport Ca(2+) into the vesicles and hydrolyze phosphosubstrates on their surface.
Arch Biochem Biophys
; 584: 79-89, 2015 Oct 15.
Article
em En
| MEDLINE
| ID: mdl-26325078
ABSTRACT
We describe the production of stable DPPC and DPPCDPPS-proteoliposomes harboring annexin V (AnxA5) and tissue-nonspecific alkaline phosphatase (TNAP) and their use to investigate whether the presence of AnxA5 impacts the kinetic parameters for hydrolysis of TNAP substrates at physiological pH. The best catalytic efficiency was achieved in DPPS 10%-proteoliposomes (molar ratio), conditions that also increased the specificity of TNAP hydrolysis of PPi. Melting behavior of liposomes and proteoliposomes was analyzed via differential scanning calorimetry. The presence of 10% DPPS in DPPC-liposomes causes a broadening of the transition peaks, with AnxA5 and TNAP promoting a decrease in ΔH values. AnxA5 was able to mediate Ca(2+)-influx into the DPPC and DPPCDPPS 10%-vesicles at physiological Ca(2+) concentrations (â¼2 mM). This process was not affected by the presence of TNAP in the proteoliposomes. However, AnxA5 significantly affects the hydrolysis of TNAP substrates. Studies with GUVs confirmed the functional reconstitution of AnxA5 in the mimetic systems. These proteoliposomes are useful as mimetics of mineralizing cell-derived matrix vesicles, known to be responsible for the initiation of endochondral ossification, as they successfully transport Ca(2+) and possess the ability to hydrolyze phosphosubstrates in the lipid-water interface.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cálcio
/
Anexina A5
/
Materiais Biomiméticos
/
Fosfatase Alcalina
/
Lipossomos
Limite:
Humans
Idioma:
En
Revista:
Arch Biochem Biophys
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Brasil