Structural characterization of the glycoinositol phospholipid membrane anchor of human erythrocyte acetylcholinesterase by fast atom bombardment mass spectrometry.

The glycoinositol phospholipid membrane anchor of human erythrocyte acetylcholinesterase (EC 3.1.1.

Structural elucidation of complex carbohydrates.

Many current problems in immunology depend on a detailed understanding of oligosaccharide and glycoconjugate structures. In contrast to other biopolymers, oligosaccharides do not have well established and sensitive analytical procedures for the determination of their structures. Additionally, oligosaccharides because of branching, linkage, and structural isomerism, pose specific complications unique to this biopolymer.

Incorporation of fluorotryptophan into triostin antibiotics by Streptomyces triostinicus.

The quinoxaline chromophores of the antibiotics produced by Streptomyces triostinicus are derived from tryptophan. Protoplasts of this organism made novel products when they were incubated with DL-5-fluorotryptophan or DL-6-fluorotryptophan. When added to batch cultures of the organism, DL-5-fluorotryptophan, at concentrations as low as 10 microM, inhibited both mycelial growth and triostin production, but gave rise to novel products.

Identification of 3 beta-hydroxy-5,7-pregnadien-20-one and 3 beta-hydroxy-5,7-androstadien-17-one as endogenous steroids in the fetal horse gonad.

The 5,7-dienes, 3 beta-hydroxy-5,7-pregnadien-20-one and 3 beta-hydroxy-5,7-androstadien-17-one were extracted from fetal horse gonads and purified by solvent partition, thin-layer chromatography and high performance liquid chromatography. The isolated steroids were identified by comparison with the synthetic steroids using ultraviolet and mass spectroscopy and by gas chromatography-mass spectroscopy. The identification of these compounds as endogenous steroids, together with the data on their biosynthesis reported previously, support the proposal that in the fetal horse gonad there is a 5,7-diene pathway biosynthesizing 3 beta-hydroxy-5,7-androstadien-17-one, which is the proposed precursor for equilin in the placenta.

Amino acid sequence around the active serine in the acyl transferase domain of rabbit mammary fatty acid synthase.

Rabbit mammary fatty acid synthase was labelled in the acyl transferase domain(s) by the formation of the O-ester intermediates after incubation with [14C]acetyl- or malonyl-CoA. Elastase peptides containing the labelled acyl groups were isolated using high performance liquid chromatography and sequenced by fast atom bombardment mass spectrometry. An identical peptide (acyl-Ser-Leu-Gly-Glu-Val-Ala) was obtained after labelling with acetyl- or malonyl-CoA.