Mass Spectral Analysis of Synthetic Peptides: Implications in Proteomics.

Sequence determination of peptides is a crucial step in mass spectrometry-based proteomics. Peptide sequences are determined either by database search or by sequencing using tandem mass spectrometry. Determination of all the theoretical expected peptide fragments and eliminating false discoveries remains a challenge in proteomics.

Detection of peptides with intact phosphate groups using MALDI TOF/TOF and comparison with the ESI-MS/MS.

A wide variety of post-translational modifications such as oxidation, phosphorylation, glycosylation, methylation, and acetylation play critical roles in cellular functions. Detection of post-translational modifications in proteins is important to understand their crucial roles in cellular functions. Identifying each modification requires special attention in mass spectral acquisition and analysis.

Inhibiting sperm pyruvate dehydrogenase complex and its E3 subunit, dihydrolipoamide dehydrogenase affects fertilization in Syrian hamsters.

Background/aims: The importance of sperm capacitation for mammalian fertilization has been confirmed in the present study via sperm metabolism. Involvement of the metabolic enzymes pyruvate dehydrogenase complex (PDHc) and its E3 subunit, dihydrolipoamide dehydrogenase (DLD) in hamster in vitro fertilization (IVF) via in vitro sperm capacitation is being proposed through regulation of sperm intracellular lactate, pH and calcium.

Methodology And Principal Findings: Capacitated hamster spermatozoa were allowed to fertilize hamster oocytes in vitro which were then assessed for fertilization, microscopically.

Association of lactate, intracellular pH, and intracellular calcium during capacitation and acrosome reaction: contribution of hamster sperm dihydrolipoamide dehydrogenase, the E3 subunit of pyruvate dehydrogenase complex.

The role of dihydrolipoamide dehydrogenase (DLD), the E3 subunit of the pyruvate dehydrogenase complex (PDHc) in hamster sperm capacitation and acrosome reaction has been implicated previously. In this study, attempt has been made to understand DLD/PDHc involvement from the perspective of pyruvate/lactate metabolism. Inhibition of DLD was achieved by the use of a specific inhibitor, 5-methoxyindole-2-carboxylic acid.

Glucose-regulated protein precursor (GRP78) and tumor rejection antigen (GP96) are unique to hamster caput epididymal spermatozoa.

The immotile testicular mammalian spermatozoon gets transformed into a motile spermatozoon during 'epididymal maturation'. During this process, the spermatozoa transit from the caput to the cauda epididymis and undergo a number of distinct morphological, biophysical and biochemical changes, including changes in protein composition and protein modifications, which may be relevant to the acquisition of motility potential. The present proteome-based study of the hamster epididymal spermatozoa of caput and cauda led to the identification of 113 proteins spots using Matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS) analysis.