Primary structure and tetrahydropteroylglutamate binding site of rabbit liver cytosolic 5,10-methenyltetrahydrofolate synthetase.

The primary sequence of 5,10-methenyltetrahydrofolate synthetase from rabbit liver was determined by amino acid sequencing of the purified enzyme. The enzyme contains 201 amino acid residues with a predicted mass of 22,779 Da. The enzyme is located in the cytosolic fraction of liver homogenates. Carbodiimide-activated 5-formyltetrahydropteroylmonoglutamate and the pentaglutamate form of the substrate both irreversibly inactivate the enzyme by forming a covalent bond to Lys-18. Non-activated 5-formyltetrahydropteroylpentaglutamate protected against this inactivation. Substrate specificity studies showed that increasing the number of glutamate residues from zero to five on 5-formyltetrahydropteroate results in a 2 order of magnitude increase in the affinity of the substrate for the enzyme but only a 3-fold increase in the value of Vmax

Usefulness of atherogenic dyslipidemia for predicting cardiovascular risk in patients with angiographically defined coronary artery disease

The identification of factors contributing to residual cardiovascular risk is important to improve the management of patients with established coronary artery disease (CAD). This study was conducted to assess the predictive value of atherogenic dyslipidemia (defined as high triglycerides and low high-density lipoprotein [HDL] cholesterol) for long-term outcomes in patients with CAD. In 284 patients (238 men, 46 women; mean age at baseline 59.2 +/- 8.9 years) with coronary stenosis (> 50% in >= 1 vessel), the presence of atherogenic dyslipidemia was prospectively associated with the incidence of major adverse cardiovascular events (MACEs) during a median follow-up of 7.8 years. MACEs were defined as cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, the recurrence of angina, and revascularization procedures. MACEs were observed in 111 (39.1%) patients with CAD. MACEs occurred more frequently in patients with atherogenic dyslipidemia (50.9%) than in those with isolated low HDL cholesterol or high triglycerides (33.0%) or with normal HDL cholesterol and triglyceride concentrations (29.2%) (p < 0.01 for trend). Kaplan-Meier survival analysis showed a decrease in event-free survival in patients with compared with those without atherogenic dyslipidemia (log-rank p = 0.006). Patients with atherogenic dyslipidemia presented with increased plasma concentrations of remnants, denser low-density lipoprotein, more atherogenic HDL particles, and insulin-resistant status. After adjustment for potential confounding variables, the magnitude of increased risk associated with atherogenic dyslipidemia was 1.58 (95% confidence interval 1.12 to 2.21, p = 0.008). In conclusion, these data provide evidence that atherogenic dyslipidemia is an independent predictor of cardiovascular risk in patients with CAD, even stronger than isolated high triglycerides or low HDL cholesterol. (c) 2007 Elsevier Inc. All rights reserved