Biomaterial Database

Considerations on the role of aspartic acid racemization in the aging process. 1977

P M Helfman, and J L Bada, and M Y Shou

Racemization of aspartyl residues in human dentine and enamel proteins has been shown to occur at a rate which corresponds to an enrichment in the D-aspartic acid content of 0.1% per year. This rate can be used to calculate the ages of living people or the in vivo lifetimes of slowly turned over proteins. We present stereochemical arguments for conformational changes in proteins as a consequence of racemized amino acid residues. In metabolically stable proteins, this phenomenon may play some part in the aging process. In renewed proteins, where certain factors may accelerate racemization, conformational changes induced by racemization could regulate protein degradation.

UI	MeSH Term	Description	Entries
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D002648	Child	A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL.	Children
D003743	Dental Enamel	A hard thin translucent layer of calcified substance which envelops and protects the dentin of the crown of the tooth. It is the hardest substance in the body and is almost entirely composed of calcium salts. Under the microscope, it is composed of thin rods (enamel prisms) held together by cementing substance, and surrounded by an enamel sheath. (From Jablonski, Dictionary of Dentistry, 1992, p286)	Enamel,Enamel Cuticle,Dental Enamels,Enamel, Dental,Enamels, Dental,Cuticle, Enamel,Cuticles, Enamel,Enamel Cuticles,Enamels
D003804	Dentin	The hard portion of the tooth surrounding the pulp, covered by enamel on the crown and cementum on the root, which is harder and denser than bone but softer than enamel, and is thus readily abraded when left unprotected. (From Jablonski, Dictionary of Dentistry, 1992)	Dentine,Dentines,Dentins
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000293	Adolescent	A person 13 to 18 years of age.	Adolescence,Youth,Adolescents,Adolescents, Female,Adolescents, Male,Teenagers,Teens,Adolescent, Female,Adolescent, Male,Female Adolescent,Female Adolescents,Male Adolescent,Male Adolescents,Teen,Teenager,Youths
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D000368	Aged	A person 65 years of age or older. For a person older than 79 years, AGED, 80 AND OVER is available.	Elderly
D000375	Aging	The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.	Senescence,Aging, Biological,Biological Aging