Fisher G, Lopez S, Peterson K, Goff T, Philip I, Gaviria R, Lorenzo N, Tsesarskaia M
Department of Chemistry, Barry University, Miami Shores, Florida 33161, USA.
Amino Acids. 2007 Jan;32(1):27-30. doi: 10.1007/s00726-006-0353-7. Epub 2006 Jun 1.
L-Aspartic acid (L-Asp) is one of the fastest racemizing amino acids such that the abnormal D-form (D-Asp) has been found in stable biological human tissues such as dentin in teeth, eye lens and brain. Earlier reports showed that there was a linear correlation between age and D-Asp in teeth. We have previously reported that significant levels of D-Asp were found in normal and osteoarthritic knee cartilage. Since cartilage is a slow regenerating tissue, we hypothesized that D-Asp should accumulate in knee cartilage and that there might be a correlation between the age of the person and the amount of D-Asp found in cartilage. Our analysis of approximately 100 samples of normal knee cartilage showed that there are detectable amounts of D-Asp (2-4% of total Asp) in knee cartilage. However, there was only a slight correlation (r = 0.35) between the age of the person and the amount of D-Asp (nmoles/g). Surprisingly, there was a better correlation between age and the amount of D-Asp in the male subjects (r = 0.57) than in the female subjects (r = 0.21).
L-天冬氨酸（L-Asp）是消旋速度最快的氨基酸之一，因此在牙齿牙本质、晶状体和大脑等稳定的人体生物组织中发现了异常的D型（D-Asp）。早期报告显示，牙齿中年龄与D-Asp之间存在线性相关性。我们之前曾报道，在正常和骨关节炎膝关节软骨中发现了显著水平的D-Asp。由于软骨是一种再生缓慢的组织，我们推测D-Asp应在膝关节软骨中积累，并且在人的年龄与软骨中发现的D-Asp量之间可能存在相关性。我们对大约100份正常膝关节软骨样本的分析表明，膝关节软骨中存在可检测到的D-Asp量（占总天冬氨酸的2-4%）。然而，人的年龄与D-Asp量（纳摩尔/克）之间仅存在轻微相关性（r = 0.35）。令人惊讶的是，男性受试者中年龄与D-Asp量之间的相关性（r = 0.57）比女性受试者（r = 0.21）更好。
