Shah, K.R.Patel, D.K.Pappachan, A.Prabha, C.R.Singh, D.D.2018-07-142024-08-142018-07-142024-08-142016Shah, K. R., Patel, D. K., Pappachan, A., Prabha, C. R., & Singh, D. D. (2016). Characterization of a Kunitz-type serine protease inhibitor from Solanum tuberosum having lectin activity. International Journal of Biological Macromolecules, 83, 259-269. doi: 10.1016/j.ijbiomac.2015.11.068141813010.1016/j.ijbiomac.2015.11.068https://kr.cup.edu.in/handle/32116/1261Plant lectins and protease inhibitors constitute a class of proteins which plays a crucial role in plant defense. In our continuing investigations on lectins from plants, we have isolated, purified and characterized a protein of about 20kDa, named PotHg, showing hemagglutination activity from tubers of Indian potato, Solanum tuberosum. De novo sequencing and MS/MS analysis confirmed that the purified protein was a Kunitz-type serine protease inhibitor having two chains (15 kDa and 5 kDa). SDS and native PAGE analysis showed that the protein was glycosylated and was a heterodimer of about 15 and 5kDa subunits. PotHg agglutinated rabbit erythrocytes with specific activity of 640H.U./mg which was inhibited by complex sugars like fetuin. PotHg retained hemagglutination activity over a pH range 4-9 and up to 80?C. Mannose and galactose interacted with the PotHg with a dissociation constant (Kd) of 1.5?10-3M and 2.8?10-3M, respectively as determined through fluorescence studies. Fluorescence studies suggested the involvement of a tryptophan in sugar binding which was further confirmed through modification of tryptophan residues using N-bromosuccinimide. Circular dichroism (CD) studies showed that PotHg contains mostly ? sheets (~45%) and loops which is in line with previously characterized protease inhibitors and modeling studies. There are previous reports of Kunitz-type protease inhibitors showing lectin like activity from Peltophorum dubium and Labramia bojeri. This is the first report of a Kunitz-type protease inhibitor showing lectin like activity from a major crop plant and this makes PotHg an interesting candidate for further investigation. ? 2015 Elsevier B.V.en-USFetuinGalactoseLectinMannoseSerine proteinase inhibitorTryptophanKunitz-type protease inhibitor, plantPeptidePlant lectinPlant proteinSerine proteinase inhibitorAnimal cell beta sheetBinding affinityControlled studyDe novo sequencingDissociation constantDrug activityDrug determinationErythrocyteGlycosylationHemagglutinationLabramia bojeriLectin like activityMedicinal plantMolecular weightNon humanPeltophorum dubium;Articlehttps://www.sciencedirect.com/science/article/pii/S0141813015301641?via%3Dihub