Vol.09 Issue-02, (July - December, 2017) ISSN: 2394-9309 (E) / 0975-7139 (P) Aryabhatta Journal of Mathematics and Informatics (Impact Factor- 5.856) Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories Aryabhatta Journal of Mathematics and Informatics http://www.ijmr.net.in email id- irjmss@gmail.com Page 30 ANALYSING AMINO ACIDS IN HUMAN GALANIN AND ITS RECEPTORS - GRAPH THEORETICAL APPROACH Suresh Singh G. a and Akhil C. K. b a Department of Mathematics, University of Kerala, Kariavattom, Thiruvananthapuram – 695581, Kerala, India, b Department of Mathematics, University of Kerala, Kariavattom, Thiruvananthapuram – 695581, Kerala, India, Acknoldgements We wish to thank Dr Achuthsankar S. Nair, Head of the Department, Department of Computational Biology and Bioinformatics, University of Kerala, Thiruvananthapuram along with the faculty members, Vijayalakshmi B. and Biji C. L. for their fruitful suggestions and constant encouragements. Abstract: Graph theoretical analysis is an important area of research in biological networks. In this work we define some new graphs called bipartite Pt-graphs and their physicochemical subgraphs for peptides/proteins and their receptors based on the physicochemical properties of amino acids. Here we analyze bipartite Pt- graphs and their physicochemical subgraphs of human galanin and its three receptors graph theoretically. From the graph theoretical analysis of bipartite Pt- graphs and the physicochemical subgraphs we get some observations about the relations among the amino acids, physicochemical properties, galanin and its receptors. By a graph theoretical parameter of physicochemical subgraphs we get all the collections of maximum independent pairs of amino acids which connect the galanin and receptors by sharing exactly  ( = 1,2,3, … ) common physicochemical properties. These analyses can be used to study all the relationships between peptide/protein ligands and their receptors and this may help in the field of drug designing. Keywords: Amino acid, galanin, galanin receptor, bipartite Pt-graph, physicochemical subgraph.