Peptide mapping of myosin light chains by high-performance liquid chromatography

Effects of column length, particle size, gradient length and flow rate on peak capacity of nano-scale liquid chromatography for peptide separations

The effects of the column length, the particle size, the gradient length and the flow rate of a nanoLC system on peptide peak capacity were investigated and compared. Columns packed with 1.7 microm and 3 microm C(18) materials into pieces of 75 microm capillary tubing of various lengths were tested with different gradient lengths and flow rates. While increasing the length of a column packed with the 1.7 microm material helped improve peptide peak capacity at the whole range of the tested gradient lengths (24-432 min), little improvement in peak capacity was observed with the increase of the length of a column packed with the 3 microm material unless a gradient longer than 50 min was carried out. Up to 30% of peak capacity increase was observed when a column's length is doubled, with little reduction in the throughput. In most cases, more than 50% of the increase in peak capacity was obtained with the reduction in the particle size from 3 microm to 1.7 microm. With the same backpressure generated, a shorter 1.7-microm-particle column outperformed a longer column packed with the 3 microm material. In a flow rate range of 100-700 nl/min, increasing the flow rate improved peak capacity for columns packed with 1.7 microm and 3 microm materials.

Myosin light chain kinase expression during smooth muscle development

The expression of smooth muscle myosin light chain kinase (MLCK) was investigated during chicken gizzard development. The molecular weight and the antigenic properties of MLCK did not change during development. The use of anion exchange high performance liquid chromatography (HPLC) enabled us to distinguish between MLCKs from post-hatched and adult chickens. A partial amino acid sequence determination of 4-day-old gizzard MLCK failed to disclose differences in the primary sequences of the two proteins. The results suggest that MLCK has the same primary sequence in all stages of gizzard development, although charge variants due to post-translational modifications may exist.

General method for the separation of cyanogen bromide digests of proteins by high-performance liquid chromatography. Rabbit skeletal troponin I

In this study, we have demonstrated the necessity for a combination of size-exclusion, ion-exchange and reversed-phase high-performance liquid-chromatography to resolve completely a protein digest. Our approach minimizes the number of steps, and the column order provides the maximum information about the properties of the fragments. The order is: (1) size-exclusion (Bio-Rad TSK-250 column), (2) strong cation-exchange (Synchropak S300 column), and finally (3) reversed-phase chromatography (Ultrapore C3). It was desirable for the first step of the procedure to be size-exclusion chromatography to produce the least number of fractions. The volatile eluent used in size-exclusion eliminated the need for subsequent sample desalting. Volatile buffers were not necessary for the ion-exchange chromatography, since the fractions were both desalted and purified in the final reversed-phase step. All column effluents were compatible with absorbance measurements at 210 nm to provide maximum sensitivity for peptide detection. The results obtained in this study strongly suggest that the combined use of three methods of separation, which utilize different selectivities (size, charge, hydrophobicity), can provide excellent resolving power for peptide separations. We believe this fast, efficient procedure should be generally applicable to other protein digests.

Myosin light chains of avian and mammalian slow muscles: peptide mapping of 2S light chains

The 2S light chains of mammalian and avian slow muscle myosin, indistinguishable by two-dimensional gel electrophoresis, have been examined by peptide mapping. The fragments obtained with S. aureus V8 protease were analysed either by gel electrophoresis or by reverse-phase high performance liquid chromatography. The peptide maps of avian 2S light chains contain fragments distinct from those of mammalian 2S light chains. Chicken and turkey LC2S appear to be more similar to each other than those from mammalian species (rat and rabbit). These results are in agreement with the relative phylogenetic distances among the four species studied here. The 2S light chain of slow muscle represent further examples of polypeptides which comigrate in two-dimensional gel electrophoresis in spite of their different peptide maps.