This chapter focuses on Lysine Biosynthesis (Yeast)

(Chlorella pyrenoidosa) is a unicellular, freshwater, green microalga. It is a nutrient-dense, alkaline-forming superfood providing protein, fiber, essential fatty acids (it is an excellent source of linolenic acid), and a full spectrum of vitamins, minerals, amino acids, enzymes, antioxidants, mucopolysaccharides, and phytonutrients. Among these nutrients are significant amounts of Vitamin A, Vitamin D, Vitamin E, Vitamin K1, all the major B vitamins (including B12); iron, calcium, potassium, phosphorus, magnesium, and zinc; an abundance of naturally occurring beta-carotene and lutein.

Singh BK, Shaner DL 1995 Biosynthesis of branched chain amino acids: From test tube to field.

The Leu3 protein of is a transcriptional regulator of genes encoding enzymes of the branched-chain amino acid biosynthetic pathways (Hu et al, 1995).

Control of lysine biosynthesis in yeast.

T1 - Loss of compartmentalization causes misregulation of lysine biosynthesis in peroxisome-deficient yeast cells

AB - To characterize the metabolic role of peroxisomes in yeast cells under physiological conditions, we performed a comprehensive meta-analysis of published microarray data. Previous studies of yeast peroxisomes have mainly been focused on the function of peroxisomes under extreme conditions, such as growth on oleate or methanol as the sole carbon source, and may therefore not be representative of the normal physiological role of yeast peroxisomes. Surprisingly, our analysis of the microarray data reveals that the only pathway responding to peroxisome deficiency in mid-log phase is lysine biosynthesis, whereas classical peroxisomal pathways such as beta-oxidation are unaffected. We show that the upregulation of lysine biosynthesis genes in peroxisome-deficient yeasts shares many characteristics with the physiological response to lysine starvation. We provide data that suggest that this is the result of a "pathological" stimulation of the Lys14p transcriptional activator by the pathway intermediate aminoadipate semialdehyde. Mistargeting of the peroxisomal lysine pathway to the cytosol increases the active concentration of aminoadipate semialdehyde, which is no longer contained in the peroxisome and can now activate Lys14p at much lower levels than in wild-type yeasts. This is the first well-documented example of pathway misregulation in response to peroxisome deficiency and will be useful in understanding the phenotypic details of human peroxisome-deficient patients (Zellweger syndrome).

Saccharomyces cerevisiae Lysine Biosynthesis

Quantitative proteomics studies of yeast that use metabolic labeling with amino acids rely on auxotrophic mutations of one or more genes on the amino acid biosynthesis pathways. These mutations affect yeast metabolism and preclude the study of some biological processes. Overcoming this limitation, it has recently been described that proteins in a yeast prototrophic strain can also be metabolically labeled with heavy amino acids. However, the temporal profiles of label incorporation under the different phases of the prototroph's growth have not been examined. Labeling trajectories are important in the study of protein turnover and dynamics, in which label incorporation into proteins is monitored across many time points. Here we monitored protein labeling trajectories for 48 h after a pulse with heavy lysine in a yeast prototrophic strain and compared them with those of a lysine auxotrophic yeast. Labeling was successful in prototroph yeast during exponential growth phase but not in stationary phase. Furthermore, we were able to determine the half-lives of more than 1700 proteins during exponential phase of growth with high accuracy and reproducibility. We found a median half-life of 2 h in both strains, which corresponds with the cellular doubling time. Nucleolar and ribosomal proteins showed short half-lives, whereas mitochondrial proteins and other energy production enzymes presented longer half-lives. Except for some proteins involved in lysine biosynthesis, we observed a high correlation in protein half-lives between prototroph and auxotroph strains. Overall, our results demonstrate the feasibility of using prototrophs for proteomic turnover studies and provide a reliable data set of protein half-lives in exponentially growing yeast. (Graph Presented).

LYS2 | SGD - Saccharomyces Genome Database | SGD

In the early 1950s, the Japanese researcher Fujimaki separated a previously undiscovered substance from a hot-water extract of chlorella that is now known as “Chlorella Growth Factor” or CGF. CGF is a nucleotide-peptide complex comprised mostly of nucleic acid derivatives. The sugars identified in the nucleotide include glucose, mannose, rhamnose, arabinose, galactose, and xylose. Amino acids found in the peptide include glutamine, alanine, serine, glycine, proline, asparagine, threonine, lysine, cysteine, tyrosine, and leucine.