Figure 5.

Correlations of Hcy metabolic enzyme expression with Hcy levels in tissues. Relative expression of selected enzymes was determined as described in Fig. 2 and expressed by relative mRNA expression levels (REU). A, B) Correlation between mRNA levels of Hcy metabolic enzymes (A) and methylation enzymes (B), and Hcy levels in mouse tissues. Tissue relative expressions of enzyme mRNA were plotted against tissue Hcy levels shown in Table 1. Linear regression analyses were performed using data points from 7 mouse tissues. Genes are classified into 2 types. Type 1 enzymes exhibited positive correlation between gene expression and Hcy levels in selected tissues. Type 2 enzymes do not correlate with tissue Hcy concentration. Enzymes 4–7 (BHMT, MTHFR, AHCY, and MTR) are members of both groups. Enzyme abbreviations are listed in Table 1.