B. S. Hartley delivered a lecture on strategy and tactics in protein chemistry, emphasizing the importance of new methods in advancing enzyme research. He discussed how the development of relevant methods has been crucial for understanding enzyme mechanisms, highlighting the role of kinetic studies, amino acid sequencing, and X-ray diffraction in determining enzyme structures. He also introduced the DNS (dansyl chloride) technique for peptide sequence analysis, which allowed for the identification of N-terminal amino acids. This method was further refined and applied to the study of enzyme sequences, leading to the development of the DNS-Edman method for determining amino acid sequences. Hartley also discussed diagonal electrophoretic techniques for the selective purification of disulphide-bridged peptides, which proved useful in determining the primary structure of proteins. These techniques were applied to various proteins, including chymotrypsin, trypsin, and elastase, revealing homologies in their disulphide bridge structures. The method was further extended to the study of serine proteinases, where disulphide bridges were identified and characterized. Hartley also discussed the use of maleic anhydride in modifying proteins to improve solubility and facilitate digestion. This technique allowed for the determination of protein subunit structures and molecular weights. Additionally, he described the use of competitive labelling to determine the pKa and reactivity of amino groups in proteins, which provided insights into the behavior of functional groups in different environments. Overall, Hartley's lecture emphasized the importance of innovative methods in protein chemistry, highlighting the role of new techniques in advancing our understanding of protein structure and function. The development of these methods has been instrumental in elucidating the complex structures of proteins and their functional properties.B. S. Hartley delivered a lecture on strategy and tactics in protein chemistry, emphasizing the importance of new methods in advancing enzyme research. He discussed how the development of relevant methods has been crucial for understanding enzyme mechanisms, highlighting the role of kinetic studies, amino acid sequencing, and X-ray diffraction in determining enzyme structures. He also introduced the DNS (dansyl chloride) technique for peptide sequence analysis, which allowed for the identification of N-terminal amino acids. This method was further refined and applied to the study of enzyme sequences, leading to the development of the DNS-Edman method for determining amino acid sequences. Hartley also discussed diagonal electrophoretic techniques for the selective purification of disulphide-bridged peptides, which proved useful in determining the primary structure of proteins. These techniques were applied to various proteins, including chymotrypsin, trypsin, and elastase, revealing homologies in their disulphide bridge structures. The method was further extended to the study of serine proteinases, where disulphide bridges were identified and characterized. Hartley also discussed the use of maleic anhydride in modifying proteins to improve solubility and facilitate digestion. This technique allowed for the determination of protein subunit structures and molecular weights. Additionally, he described the use of competitive labelling to determine the pKa and reactivity of amino groups in proteins, which provided insights into the behavior of functional groups in different environments. Overall, Hartley's lecture emphasized the importance of innovative methods in protein chemistry, highlighting the role of new techniques in advancing our understanding of protein structure and function. The development of these methods has been instrumental in elucidating the complex structures of proteins and their functional properties.