Systematic Identification of Yeast Proteins Extracted into Model Wine during Aging on the Yeast Lees

Abstract

Total protein and protein-associated mannan concentrations were measured, and individual proteins were identified during extraction into model wines over 9 months of aging on the yeast lees following completion of fermentations by seven wine strains of Saccharomyces cerevisiae. In aged wines, protein-associated mannan increased about 6-fold (+/-66%), while total protein only increased 2-fold (+/-20%), which resulted in a significantly greater protein-associated mannan/total protein ratio for three strains. A total of 219 proteins were identified among all wine samples taken over the entire time course. Of the 17 "long-lived" proteins detected in all 9 month samples, 13 were cell wall mannoproteins, and four were glycolytic enzymes. Most cytosolic proteins were not detected after 6 months. Native mannosylated yeast invertase was assayed for binding to wine tannin and was found to have a 10-fold lower affinity than nonglycosylated bovine serum albumin. Enrichment of mannoproteins in the aged model wines implies greater solution stability than other yeast proteins and the possibility that their contributions to wine quality may persist long after bottling.

Protein Structures among Bio-Ethanol Co-Products and Its Relationships with Ruminal and Intestinal Availability of Protein in Dairy Cattle

“…As opposed to “wet” chemical analysis, infrared spectroscopic techniques, such as Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT), have the potential to reveal molecular structures of proteins. These techniques have been implemented to study the protein secondary structure of feeds [2,3]. …”

Fructose-1,6-bisphosphatase, Malate Dehydrogenase, Isocitrate Lyase, Phosphoenolpyruvate Carboxykinase, Glyceraldehyde-3-phosphate Dehydrogenase, and Cyclophilin A are secreted inSaccharomyces cerevisiaegrown in low glucose

“…GAPDH is a cell surface protein, 27,28 whereas Cpr1p has been identified in the culture media in Saccharomyces cerevisiae in large-scale secretomic/extraction studies. 29,30 Our results indicated that approximately 33.7-76.7% of these enzymes were secreted in glucose-starved cells. Given that these proteins do not contain typical ER signal sequence, they are secreted via the non-classical pathway.…”

The impact of different ale brewer’s yeast strains on the proteome of immature beer

“…It is reported that Exg1, Bgl2 and Uth1 are anchored to the yeast cell wall by di-sulphide bridges, as they are released from yeast cells upon treatment with reducing agents as DTT [34,35]. During wine fermentations, yeast cells release Exg1 and Bgl2 from the cell wall to the wine [36]. In beer, Fasilo et al (2010) identified Exg1, Bgl2 and Uth1 among the 40 protein fragments, originating from S. cerevisiae [4], and very recently the presence of these three full-length proteins have also been identified in different commercial beers [5].…”