Steroids made it possible: Organic mass spectrometry

Structure Determination of Natural Products by Mass Spectrometry

I review laboratory research on the development of mass spectrometric methodology for the determination of the structure of natural products of biological and medical interest, which I conducted from 1958 to the end of the twentieth century. The methodology was developed by converting small peptides to their corresponding polyamino alcohols to make them amenable to mass spectrometry, thereby making it applicable to whole proteins. The structures of alkaloids were determined by analyzing the fragmentation of a known alkaloid and then using the results to deduce the structures of related compounds. Heparin-like structures were investigated by determining their molecular weights from the mass of protonated molecular ions of complexes with highly basic, synthetic peptides. Mass spectrometry was also employed in the analysis of lunar material returned by the Apollo missions. A miniaturized gas chromatograph mass spectrometer was sent to Mars on board of the two Viking 1976 spacecrafts.

Rearrangement and fragmentation of estrogen ether ions: new aspects found with Fourier transform ion cyclotron resonance mass spectrometry

Electrospray ionization mass spectra of several di- and tri-hydroxy-estratriene-ethers, as well as estradiol and estriol, have been investigated by high-resolution mass spectrometry. The fragmentation mechanisms leading to the loss of water molecules from the protonated molecular ion have been rationalized by using protecting groups as well as mass spectrometric means such as collision-induced dissociation and infrared multi-photon dissociation. The unexpected observation of a simultaneous loss of two water molecules from the protonated estradiol ethers and of three water molecules from the protonated estriol ethers has been discussed with respect to varying reaction mechanisms and rearrangements. Results und conclusions derived from them were obtained by adequate deuterated ethers.

Four decades of structure determination by mass spectrometry: from alkaloids to heparin

The early (1950's and 1960's) use of mass spectrometry in natural products chemistry and its evolution to the present significance in biochemistry is recounted. This methodology allowed the facile and speedy determination of the structure of a number of indole alkaloids, such as sarpagine, quebrachamine, and two groups isolated from the roots of Aspidosperma quebracho blanco. At the same time, the first strategy for the sequencing of small peptides by mass spectrometry was demonstrated. It slowly advanced, over a period of two decades, to an important alternative of the ubiquitous automated Edman degradation. Further advances in methodology and instrumentation established mass spectrometry as today's indispensable tool for the characterization of proteins in biochemistry and biology. A new concept of the ionization of highly acidic compounds as the protonated complexes with basic peptides, which allows the accurate determination of the molecular weights of the former, a highly sensitive method for the sequencing of heparin fragments and related sulfated glycosaminoglycans was developed more recently.

The massachusetts institute of technology mass spectrometry school

The events that led to the establishment of organic and biochemical mass spectrometry at MIT by the author in 1958, and its growth over the past three and one-half decades are briefly chronicled. A major emphasis is placed on the work with graduate students and postdoctoral researchers who were educated in the field and in turn further contributed to the training of others. An attempt is made at the construction of a genealogy encompassing - 7 to + 2 generations (the author representing 0).