Pabitra Kumar Maitra earned his BSc (Hons), MSc Tech and PhD degrees from University of Calcutta. For his PhD thesis, Maitra studied different metabolic pathways in Streptomyces olivaceous, but his landmark contribution was on the pathways of glucose dissimilation in S. olivaceous. He served as the Professor of Molecular Biology, Tata Institute of Fundamental Research, Mumbai; Emeritus Scientist (CSIR), Indian Institute of Technology, Mumbai and Visiting Professor at Agharkar Research Institute, Pune.
Academic and Research Achievements: Maitra left in 1960 for the Johnson Research Foundation for Medical Physics in the University of Pennsylvania at Philadelphia, USA to work as a postdoctoral fellow. There he published a series of incisive papers on energy metabolism and the metabolism of glucose and ethanol in diverse systems like Escherichia coli baker’s yeast, ascites tumor cells, pigeon heart and electrophorus, with Britton Chance and Ronald Estabrook. Maitra developed specially sensitive fluorometric methods to assay the substrates and enzymes of glycolysis and these enabled him to discover the existence of oscillatory phenomena in the glycolytic pathway. Back in India in 1963, Maitra joined the Molecular Biology Unit of the Tata Institute of Fundamental Research, Bombay. There he investigated how metabolic flux was regulated and homeostasis maintained in Escherichia coli and Saccharomyces cerevisiae, when enzymes in the glycolytic pathway were considerably reduced or enhanced. He decided to use the genetic approach along with the routine biochemical approach. Selection of mutants lacking glycolytic enzymes proved difficult, because of impermeability of cells towards phosphorylated intermediates. Maitra cleverly used glycerol and succinate and subsequently 2-deoxyglucose, to grow these mutants as glucose was found to be toxic. He successfully obtained the mutants both in coli and in yeast. This indeed was a breakthrough in yeast biochemical genetics and Maitra emerged as the pioneer in the area of genetic and biochemical dissection of the yeast glycolytic pathway. Maitra isolated and characterized structural and regulatory mutations affecting almost all the enzymes of the glycolytic pathway of yeast including mutations affecting transcription of the pyruvate decarboxylase gene and in genes for structural and regulatory subunits of phosphofructokinase.
Other Contributions: Pabitra Kumar Maitra was a remarkable guide to his students, both academically and otherwise, and inculcated in them a philosophy of practicing science that was strikingly different from what appears to be the norm in India today. Even though he only spent a relatively short period of time at the Agharkar Research Institute at Pune after his retirement from TIFR, Maitra is remembered there even today for having completely rejuvenated the student community.
Awards and Honours: Maitra was awarded the Jagadis Chandra Bose Medal of INSA (1992). He is a Fellow of the Indian Academy of Sciences, Bangalore.