A novel method for multiplex protein biomarker analysis of human serum using quantitative MALDI mass spectrometry.

In this work, we have extended our previously proposed approach for determining protein concentrations in human serum (using MALDI-TOF mass spectrometry) to include simultaneous analysis of several proteins associated with acute inflammation (alpha-2-macroglobulin, fetuin-A, serum amyloid A1). This technique can be used to diagnose systemic inflammation and provides results in 4-5 h. The developed approach was verified using standard immunological methods (ELISA).

A mass spectrometric approach to study the interaction of amyloid β peptides with human α-2-macroglobulin.

We used MALDI-MS to study the interaction of amyloid β (Aβ) peptides with alpha-2-macroglobulin (α2M). The binding of amyloid beta (Aβ) peptides to alpha-2-macroglobulin (α2M) was found to inhibit the ability of trypsin to cleave out the peptide α2M 705-715 (Pep-α2M) from α2M. This was observed with both purified α2M and α2M in human serum.

Quench me if you can: Alpha-2-macroglobulin trypsin complexes enable serum biomarker analysis by MALDI mass spectrometry.

One of the main functions of alpha-2-macroglobulin (A2M) in human blood serum is the binding of all classes of protease. It is known that trypsin, after such interaction, possesses modified proteolytic activity. Trypsin first hydrolyzes two bonds in A2M's 'bait region', and the peptide VGFYESDVMGR is released from A2M.

Absolute Quantitation of Proteins by Acid Hydrolysis Combined with Amino Acid Detection by Mass Spectrometry.

Amino acid analysis is among the most accurate methods for absolute quantification of proteins and peptides. Here we combine acid hydrolysis with the addition of isotopically labeled standard amino acids and analysis by mass spectrometry for accurate and sensitive protein quantitation. Quantitation of less than 10 fmol of protein standards with errors below 10% has been demonstrated using this method.

A conservative mutant of a proteolytic fragment produced during fibril formation enhances fibrillogenesis.

The fibrillogenesis of a peptide corresponding to residues 35-51 of human α-lactalbumin (¹GYDTQAIVENNESTEYG¹⁷) can be dramatically enhanced by the addition of a tetrapeptide TDYG homologous to its C-terminus (TEYG). Generation of spontaneous hydrolytic products similar to this peptide was demonstrated by mass-spectrometry analysis of GYDTQAIVENNESTEYG peptide solution components during fibrillogenesis. Possible mechanisms and roles of short peptides in protein metabolism are discussed.

Absolute quantitation of proteins by acid hydrolysis combined with amino acid detection by mass spectrometry.

Amino acid analysis is among the most accurate methods for absolute quantification of proteins and peptides. Here, we combine acid hydrolysis with the addition of isotopically labeled standard amino acids and analysis by mass spectrometry for accurate and sensitive protein quantitation. Quantitation of less than 10 fmol of protein standards with errors below 10% has been demonstrated using this method.

The N-domain of angiotensin-converting enzyme specifically hydrolyzes the Arg-5-His-6 bond of Alzheimer's Abeta-(1-16) peptide and its isoAsp-7 analogue with different efficiency as evidenced by quantitative matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Chronic imbalance between production and degradation of the human amyloid-beta peptide (Abeta) is assumed to play an important role in pathogenesis of Alzheimer's disease (AD). Post-translational modifications of Abeta could influence its interactions with specifically cleaving proteases and, therefore, perturb the Abeta homeostasis. The angiotensin-converting enzyme (ACE) was previously shown to degrade non-modified Abeta in vitro and in cells.

Novel repressor of the human FMR1 gene - identification of p56 human (GCC)(n)-binding protein as a Krüppel-like transcription factor ZF5.

A series of relatively short (GCC)(n) triplet repeats (n = 3-30) located within regulatory regions of many mammalian genes may be considered as putative cis-acting transcriptional elements (GCC-elements). Fragile X-mental retardation syndrome is caused by an expansion of (GCC)(n) triplet repeats within the 5'-untranslated region of the human fragile X-mental retardation 1 (FMR1) gene. The present study aimed to characterize a novel human (GCC)(n)-binding protein and investigate its possible role in the regulation of the FMR1 gene.

Absolute quantitation of proteins by a combination of acid hydrolysis and matrix-assisted laser desorption/ionization mass spectrometry.

Quantitation by mass spectrometry is increasingly used to monitor protein levels in biological samples. Most of the current methods are based on the relative comparison of protein quantities but are not suited for the determination of the absolute amount of a given protein. Here we describe a method for the absolute quantitation of proteins that is based on amino acid analysis by matrix-assisted laser desorption/ionization mass spectrometry.