Secondary amines isolated from venom gland of dolichoderine antTechnomyrmex albipes.

A series of unsaturated secondary amines have been isolated from the dolichoderine antTechnomyrmex albipes (F. Smith). The major components of the mixture have been shown by spectroscopic procedures to be dinon-8-enylamine, andN-hept-6-enylnon-8-enamine, and these structural assignments have been confirmed by synthesis. Mass spectrometry indicates the presence of trace amounts of the bis C11 amine and the C9-C11 amine. The four amines, present in total at approximately 2.8µg/ant, are located in the gaster of the insect in a gland that is considered to be the venom gland although it is atypical from a morphological standpoint.

Lactoperoxidase haem, an iron-porphyrin thiol.

The haem prosthetic group of lactoperoxidase can be prepared from the enzyme in high yield by reductive cleavage with mercaptoethanol in 8 M-urea under mild conditions. The product yields porphyrins, after removal of iron, which show visible spectroscopic properties similar to protoporphyrin but are considerably more polar. In the presence of iodoacetamide, a different product is obtained by reductive cleavage. The proton n.m.r. and mass spectra of this compound indicate that the prosthetic group of the enzyme is the iron complex of 18-mercaptomethyl-2,7,12-trimethyl-3,8-divinylporphyrin-13,17-d ipropionic acid. It is proposed that the unusual strength of binding of the prosthetic group to the apoprotein is due to formation of a disulphide bond from a cysteine residue to the porphyrin thiol.

Gas chromatographic/mass spectrometric methodology for simultaneous assay of salsolinol, dopamine, norepinephrine, dihydroxyphenylacetic acid and dihydroxyphenylethanol.

Synthesis of deuterated (2H4)salsolinol from (2H4)dopamine via a Pictet-Spengler condensation is described. This (2H4)salsolinol is an ideal internal standard to determine picomole (ng) amounts of salsolinol (SAL) in a variety of sample types including urine, plasma, beverages and fruits. The deuterated standard is completely free of contamination by the non-deuterated species. The extraction procedure described is fast, highly efficient and does not lead to artifactual salsolinol formation even in the face of high dopamine concentrations. As well as SAL the method described allows simultaneous determination of norepinephrine (NE), dopamine (DA) and its two metabolites dihydroxyphenylacetic acid (DOPAC) and dihydroxyphenylethanol (DOPET). Each of the analytes is measured as its trifluoroacetyl derivative. Using trifluoroacetic anhydride in conjunction with trifluoroethanol allows simultaneous one-step derivatization of the acid function of DOPAC. All compounds were measured in the single ion monitoring (SIM) mode and quantified using appropriate deuterated internal standards. SAL, DA, DOPET, DOPAC and NE have been quantified in a variety of food and beverage sources. Soy sauce and dried banana have been identified as rich dietary sources of SAL. These data suggest diet should be considered a potentially important source of 'mammalian alkaloids' such as SAL, and the presence of SAL in mammalian systems is not necessarily evidence for an in vivo Pictet-Spengler condensation.

Comparison of high-performance liquid chromatography with electrochemical detection and gas chromatography-mass fragmentography for the assay of salsolinol, dopamine and dopamine metabolites in food and beverage samples.

High-performance liquid chromatography with electrochemical detection (HPLC-ED) and combined gas chromatography--mass spectrometry in the single-ion monitoring mode (GC--MS-SIM) have been used for the determination of salsolinol, dopamine, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxyphenylethanol and norepinephrine in a selection of food and beverage samples. The unique specificity of the SIM mode allows a simple one-step extraction to be used even for complex sample matrices. We have been able to demonstrate the quantitative and qualitative advantages offered by GC--MS over HPLC--ED by direct comparison of the chromatographic data obtained. We demonstrate that the specificity of SIM and the benefits offered by the incorporation of deuterated internal standards make GC--MS-SIM the method of choice for valid identification and precise quantitation of salsolinol, dopamine and dopamine metabolites in a complex sample matrix.

Haematoporphyrin diacetate: a probe to distinguish malignant from normal tissue by selective fluorescence.

Haematoporphyrin diacetate has been synthesized and purified. Following introduction into mice bearing squamous-cell carcinomas it was found to produce a fluorescence of the tumour tissue which was much stronger than that of the surrounding normal tissue. Haematoporphyrin diacetate was also shown to be the major active component of the impure compound known as haematoporphyrin derivative which has been widely used in tumour fluorescence studies.