Isolation and intracellular localization of insulin-like proteins from leaves of Bauhinia variegata
Braz. j. med. biol. res
; 39(11): 1435-1444, Nov. 2006. ilus, graf
Article
in En
| LILACS
| ID: lil-437826
Responsible library:
BR1.1
ABSTRACT
Evidence based on immunological cross-reactivity and anti-diabetic properties has suggested the presence of insulin-like peptides in plants. The objective of the present study was to investigate the presence of insulin-like proteins in the leaves of Bauhinia variegata ("pata-de-vaca", "mororó"), a plant widely utilized in popular medicine as an anti-diabetic agent. We show that an insulin-like protein was present in the leaves of this plant. A chloroplast protein with a molecular mass similar to that of bovine insulin was extracted from 2-mm thick 15 percent SDS-PAGE gels and fractionated with a 2 x 24 cm Sephadex G-50 column. The activity of this insulin-like protein (0.48 mg/mL) on serum glucose levels of four-week-old Swiss albino (CF1) diabetic mice was similar to that of commercial swine insulin used as control. Further characterization of this molecule by reverse-phase hydrophobic HPLC chromatographic analysis as well as its antidiabetic activity on alloxan-induced mice showed that it has insulin-like properties. Immunolocalization of the insulin-like protein in the leaves of B. variegata was performed by transmission electron microscopy using a polyclonal anti-insulin human antibody. Localization in the leaf blades revealed that the insulin-like protein is present mainly in chloroplasts where it is also found associated with crystals which may be calcium oxalate. The presence of an insulin-like protein in chloroplasts may indicate its involvement in carbohydrate metabolism. This finding has strengthened our previous results and suggests that insulin-signaling pathways have been conserved through evolution.
Full text:
1
Collection:
01-internacional
Database:
LILACS
Main subject:
Chloroplasts
/
Plant Leaves
/
Insulin-Like Growth Factor Binding Proteins
/
Bauhinia
/
Diabetes Mellitus, Experimental
/
Hypoglycemic Agents
Limits:
Animals
Language:
En
Journal:
Braz. j. med. biol. res
Journal subject:
BIOLOGIA
/
MEDICINA
Year:
2006
Document type:
Article
Affiliation country:
Brazil
Country of publication:
Brazil