Influence of temperature on secretion and functionality of lupin seed γ‐conglutin

BACKGROUND: Basic 7S globulins, a group of proteins commonly found in legumes, undergo the intriguing phenomenon ofrelease from the seeds into hot water. γ-Conglutin is a representative of this group of proteins found in lupin seeds. The phys-iological significance and the molecular mechanism of the selective release of γ-conglutin from lupin seeds remain unknown.Therefore, the presented study aimed to determine changes in the functionality of this protein in response to the high temper-ature occurring during lupin seed incubation.
RESULTS: It was confirmed that the main protein fraction released from the seeds during high-temperature incubation wasγ-conglutin. The incubation condition favours the occurrence of this protein in a monomeric form, and the temperature usedcorresponds to its midpoint unfolding temperature. Subsequent analysis carried out on the γ-conglutin monomer revealedchanges in its functionality after heat shock. The thermally treated protein shows a considerable increase in its interactionstrength with flavonoids. Moreover, the inhibitory activity against glycoside hydrolases was enhanced when γ-conglutin mono-mer was exposed to specific temperatures.
CONCLUSION: The results of the present study provide a potential explanation of the physiological relevance of γ-conglutin andshed new light on a possible mechanism of its activation upon specific heat treatment. This knowledge will help characterisehomologous proteins, which are commonly found in other legumes and undergo a similar heat-induced secretion phenomenon.© 2021 Society of Chemical Industry.