The effect of pea albumin 1F on glucose metabolism in mice.

Pea albumin 1F (PA1F), a plant peptide isolated from pea seeds, can dramatically increase blood glucose concentration by subcutaneous injection with a dosage of 5 or 10 microg/g (body weight) in normal and type II diabetic mice (KK/upj-Ay). The voltage-dependent anion channel 1 (VDAC-1) has been identified as the PA1F binding protein from mice pancreatic cell membrane, which may be involved in the regulation of enhancing blood glucose in response to PA1F binding. The results clearly show that peptide-signaling molecules from plants can affect mammalian physiological functions, especially, in association with glucose metabolism.

Activity of the plant peptide aglycin in mammalian systems.

A 37 residue peptide, aglycin, has been purified from porcine intestine. The sequence is identical to that of residues 27-63 of plant albumin 1 B precursor (PA1B, chain b) from pea seeds. Aglycin resists in vitro proteolysis by pepsin, trypsin and Glu-C protease, compatible with its intestinal occurrence and an exogenous origin from plant food. When subcutaneously injected into mice (at 10 microg.g(-1) body weight), aglycin has a hyperglycemic effect resulting in a doubling of the blood glucose level within 60 min. Using surface plasmon resonance biosensor technology, an aglycin binding protein with an apparent molecular mass of 34 kDa was detected in membrane protein extracts from porcine and mice pancreas. The polypeptide was purified by affinity chromatography and identified through peptide mass fingerprinting as the voltage-dependent anion-selective channel protein 1. The results indicate that aglycin has the potential to interfere with mammalian physiology.