Letters: January 2023

Inorganic chemistry plays key roles in biology. Martin Hughes, who has died aged 84, made seminal contributions in enzymology, toxicity, oxygen activation proteins, metals in medicine, environmental chemistry, and biomineralisation.

Hughes’s scientific career was seeded by his father, who made important contributions to hot-dip galvanisation in the 1940s. Born in Swansea, Martin stayed there for a BSc and PhD, during which time he married Jenny Collard in 1961. His 1962 thesis was entitled Mechanisms of Nitrosation Reactions, a topic that shaped his future. Most of his career was spent at Queen Elizabeth College (QEC), a small, single-faculty, multidisciplinary constituent college in Kensington within the University of London. There, his productive collaborations with biologists, which underpinned his subsequent career, were fostered, resulting in his monograph The Inorganic Chemistry of Biological Processes, published in 1972. His first microbiological collaboration at QEC was with Don Kelly, succeeded by myself upon the departure of Kelly to a chair at Warwick. Our collaboration enabled supervision of many talented postgraduates at the chemistry-microbiology interface, many peer-reviewed papers and a book. Collaborations were disrupted, but not broken, by the merger of QEC, Chelsea College and King’s College London in 1985. Until the eventual sale of the QEC site, Hughes (who was appointed professor in 1990) made valiant efforts to travel between the King’s Strand campus and his congenial, multidisciplinary home in Kensington.

A further pointer to later achievements appeared in a highly cited paper on the decomposition of trioxodinitrate (Angeli’s salt), used as a source of the metastable nitroxyl, and hence nitric oxide, a critical signalling molecule and toxic gas in biological systems. His expertise in preparing nitric oxide and insights into the complexities of its chemistry and its congeners in solution led to numerous publications and the discovery of the link between nitric oxide and a member of the ancient globin family, namely a bacterial flavohaemoglobin, now regarded as the most important nitric oxide detoxification enzyme in microbes.

A meeting with Jack Barrett, a colleague at King’s, led to the commercial exploitation of metal-microbe interactions. Moderately thermophilic chemolithotrophic bacteria that I isolated were used to oxidise low-grade pyritic gold-bearing ores, thus destroying the pyrite lattice and rendering previously intractable ore residues amenable to gold recovery by complexation with cyanide. The technology and large-scale pilots were funded by venture capitalists in Perth, Australia, and led to an extant bio-mining and bio-leaching company, BacTech, offering environmentally friendly technology.

Hughes was a popular, sought-after and inspiring university teacher who generated enthusiasm and respect in students and a wider audience. Despite intensive workloads, he was unfailing in his patience with, and compassion for, those he worked with, especially those having difficulties in their studies or private lives. He was one of the most sympathetic and kindly men imaginable, consistent with his deep religious faith. He could see the same hand of Providence in the natural world and in the Bible, which he studied with the same rigour as his chemistry. He was as engaging in his lectures on Bible prophecy as he was in dissertations of chemistry.

Hughes is survived by his three sons, Jonathan, Richard and Simon. I am indebted to them and to Simon Collard for information and encouragement.

Robert Poole FRSC
Sheffield, UK