[Glycine in synaptic vesicles of bovine cortex]

Microelectrophoresis and auxilary micromethods

In this retrospect of approximately 30 years of work with micromethods, some of them developed in our own laboratory, their principles and application to different separation problems are described, such as one- and two-dimensional microelectrophoresis in capillaries and microslab gels, isoelectric focusing in capillaries or microslab gels, microchromatography, microphotometry, and microfluorometry for qualitative and quantitative evaluation of separation patterns. In addition, some useful auxiliary methods are also described, e.g., a method for quantitative protein determination in a microliter volume when neither the volume nor the protein content in that volume are known, and methods for the determination of glycoproteins, amino acids, and sugars in the picomole range.

Amino acids in the synaptic vesicle fraction from calf brain: content, uptake and metabolism

A synaptic vesicle fraction was prepared from calf brain cortex, containing 10 identified amino acids and two unidentified ninhydrin-positive compounds, one of which is apparently a peptide. The most plentiful amino acids were taurine (1.8 nmol/g original tissue), glutamic acid (1.8), serine (0.9), aspartic acid (0.8) and GABA (0.8); the others identified were cysteic acid (or cysteinesulphinic acid), glutamine, alanine, glycine and lysine. The unknown peptide occurred in a high concentration (about 16 alanine equivalents/g), and contained mainly aspartic acid and serine. Cysteic acid (or cysteinesulphinic acid) also occurred in relatively high amounts, but its peak contained acid-labile impurities. The influx of [14C]glutamate into the vesicles took place by means of non-saturable migration, while two saturable systems having very similar properties were dominant only at low glutamate concentrations. Influx constants for these quantitatively low uptake systems were Km, 34 and 92 micrometer, and Vmax, 33 and 49 nmol/min/g obtained by v versus v/S plot. Almost the same values were also obtained by a 1/v versus 1/S plot. GAD and GABA-T activities in the vesicles were only 1/200th of those in the synaptosomes.