BIOC 2351- BIOCHEMISTRY INAME: - IBRAHIM LUNATI.D. #: - 20053845SUBJECT: - ESSAY- CRITIQUE ON THE ARTICLE- PHOSPHORYLATION IN YEASTPHOSPHORYLATION IN YEASTBackground: -Phosphorylation is the addition of a phosphate (PO4) group to a protein or other organic molecule. Protein phosphorylation in particular plays a significant role in a wide range of cellular processes. In Biochemistry protein phosphorylation has made a significant contribution in researches throughout different biological fields. If we look at the previous researches, in 1906 Phoebus Levene at Rockefeller institute, identified phosphate in the protein Vitellin and after that in 1933 he detected phosphoserine in Casein, a m ...view middle of the document...
Phosphorylation occurs mostly on multiple distinct sites on a given protein. Phosphorylation of any site on a given protein can change function of localization of that protein. Within a protein, phosphorylation can occur on several amino acids. Phosphorylation on serine is most common, followed by threonine.. Protein kinases act on and modify the activity of specific proteins. These are used extensively to transmit signals and control complex processes in cells. Up to 500 different kinases have been identified in humans. A typical eukaryotic cell has the capacity to make about 30,000 different proteins, which catalyze thousands of different reactions involving many metabolites. Cyclin-dependent kinases (CDK) belong to a group of protein kinases originally discovered as being involved in the regulation of the cell cycle.CDKs phosphorylate proteins on serine and threonine amino acid residues: they are serine/threonine kinases. A cyclin-dependent kinase is activated by association with a cyclin, forming a cyclin-dependent kinase complex.One of the terms to understand which is used in the article is a 'sequence motif', which is a nucleotide or an amino acid sequence pattern that is widespread and has, or is conjectured to have a biological significance. Within a sequence or database of sequences, researchers search and find motifs using computer-based techniques of sequence analysis, such as BLAST. Bioinformatics field tends to use such techniques. The new technology in market these days is the protein-chip technology which allows thorough analysis of biochemical activities and can be used to analyze protein kinases as well. Protein microarrays making use of new developments in protein engineering and detection have recently emerged. The basic construction of such protein chips has some similarities to DNA chips, such as the use of glass or plastic surface dotted with an array of molecules. With fluorescent markers or other methods of detection revealing the spots that have captured these proteins, protein micro arrays are being used as powerful tools in high-throughput proteomics and drug discovery. At this time, protein-chip technology concentrates on understanding molecular pathways that in turn lead to useful information for drug discovery and which can be applied to molecular diagnostics.CRITIQUE: -Realizing the importance of protein phosphorylation which controls many cellular processes, the authors of this article have identified over 4000 phosphorylation events which involved over a thousand proteins. They used the proteome-chip technology to describe the in vitro substrates recognized by the protein kinases. The authors believe that the results will shed light on mechanisms and roles of protein phosphorylation in eukaryotes. This is understood as protein phosphorylation controls many processes in the cells. Moreover yeasts possess many protein kinases and serve as good organisms for study.The authors analyzed different protein kinases al...
