Why are there proteins in the urine of healthy people?

Hua

et al. 2020

Preprint

Self Cite

Aging is an inevitable course of life. Additionally, the risk of chronic diseases or cancer increases with age. The comprehensive identification of signs related to aging can be beneficial for the prevention and early diagnosis of geriatric diseases. The comparison of global modifications in the urine proteome is a means of multidimensional information mining. This approach is based on urine, in which changes from whole-body metabolism can accumulate. This study used the urine of healthy people at different ages (22 children, 10 young people, 6 senior people) as the research object and using high-resolution tandem mass spectrometry, label-free quantitation combined with non-limiting modification identification algorithms and random group test, compared the differences in protein chemical modifications among three groups. The results show that multi-sites oxidative modifications and amino acid substitutions are noticeable features that distinguish these three age groups of people. The proportion of multi-site oxidations in urine proteins of senior (29.76%) is significantly higher than the young group (13.71% and 12.97%), which affect the biological processes of various proteins. This study could provide a reference for studies of aging mechanisms and biomarkers of age-related disease.

Section: Discussionmentioning

confidence: 99%

Oxidations and amino acid substitutions in urinary proteins are the distinguishing characteristics of aging

Hua

et al. 2020

Preprint

Self Cite

“…Even the common physiological process of hunger can be analysed to characterize the urine proteome (Yuan & Gao, 2017). However, the comparison of the global proteome chemical modifications in two kinds of body fluids (plasma and urine) showed the differences in modifications between different types of samples (Liu, Zhao, Pan, & Gao, 2020). Based on the importance of chemical modifications in the human plasma proteome, this study attempted to compare the differences in the global chemical modification levels of the plasma proteome at two different age groups, as determined by high-resolution tandem mass spectrometry combined with non-limiting modification identification (Open-pFind).…”

Section: Introductionmentioning

confidence: 99%

Global chemical modifications comparison of human plasma proteomes from two different age groups

Zhao

et al. 2020

Preprint

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The chemical modification of proteins refers to the covalent group reaction involved in their amino acid residues or chain ends which, in turn, change the molecular structure and function of the proteins. There are many types of molecular modifications in the human plasma proteome, such as phosphorylation, methylation, and acetylation. In this study, two groups of human plasma proteome at different age groups (old and young) were used to perform a comparison of global chemical modifications, as determined by tandem mass spectrometry (MS/MS) combined with non-limiting modification identification algorithms. The sulfhydryl in the cysteine A total of 4 molecular modifications were found to have significant differences: the succinylation and phosphorylation modification of cysteine (Cys, C) and the modification of lysine (Lys, K) with threonine (Thr, T) were significantly higher in the old group than in the young group, while the carbamylation of lysine was lower in the young group. Cysteine residue is an important group for forming disulphide bonds and maintaining the structure of the protein. Differential cysteine-related sulfydryl modifications may cause structural and functional changes. Lysine is a basic amino acid, and the modification of its amino group will change the charge state of the protein, which may affect the structure and function of the protein. In summary, four types of protein chemical modifications and substitutes were found to be significantly different in the plasma proteome in different age groups and their probabilities of random generation are lower by passing random grouping test. We speculate that there is an increase in certain modified proteins in the blood of the old people which, in turn, changes the function of those proteins. This change may be one of the reasons why the old people are more likely than the young people to be at risk for age-related diseases, such as metabolic diseases, cerebral and cardiovascular diseases, and cancer.

“…Even the common physiological process of hunger can be analyzed to characterize the urine proteome 16 . However, the comparison of the global proteome chemical modifications in two kinds of body fluids (plasma and urine) showed the differences in modifications between different types of samples 17 . Based on the importance of chemical modifications in the human plasma proteome, this study attempted to compare the differences in the global chemical modification levels of the plasma proteome at two different age groups, as determined by high-resolution tandem mass spectrometry combined with non-limiting modification identification (Open-pFind).…”

mentioning

confidence: 99%

Global chemical modifications comparison of human plasma proteome from two different age groups

Zhao

et al. 2020

Sci Rep

Self Cite

In this study, two groups of human plasma proteome at different age groups (old and young) were used to perform a comparison of global chemical modifications, as determined by tandem mass spectrometry (MS/MS) combined with non-limiting modification identification algorithms. The sulfhydryl in the cysteine A total of 4 molecular modifications were found to have significant differences passing random grouping tests: the succinylation and phosphorylation modification of cysteine (Cys, C) and the modification of lysine (Lys, K) with threonine (Thr, T) were significantly higher in the old group than in the young group, while the carbamylation of lysine was lower in the young group. We speculate that there is an increase in certain modified proteins in the blood of the old people which, in turn, changes the function of those proteins. This change may be one of the reasons why old people are more likely than young people to be at risk for age-related diseases, such as metabolic diseases, cerebral and cardiovascular diseases, and cancer.