Purified cytochrome c oxidase CO complex from beef heart has been studied by Fourier transform infrared absorbance difference spectroscopy. Photolysis at 10-20 Kelvin results in dissociation of a3FeCO, formation of CuBCO, and perturbation of the a3-heme and CuB complex. The vibrational perturbation spectrum between 900 and 1700 cm-1 contains a wealth of information about the binuclear center. Appearance in infrared photoperturbation difference spectra of virtually all bands previously reported from resonance Raman spectra indicate the importance of polarization along the 4-vinyl:8-formyl axis, which results in the reduction of heme symmetry to C2v. Frequency-shifted bands due to the 8-formyl and 4-vinyl groups of the a3-heme have been identified and quantitated. The frequency shifts have been interpreted as being due to a change in porphyrin polarization with change in spin state of the iron by photodissociation of CO or perturbation of the CuB coordination complex.

Objectives: To determine relative effects of diets high in synthetic sources of myristic (14:0), palmitic (16:0) or stearic (18:0) acid on concentrations and metabolism of serum lipoproteins. Design: Eighteen healthy women participated in a three-way cross-over study for ®ve week periods separated by seven week washout periods, diets were assigned in random order. Subjects: Premenopausal women, not on medication, were from three races (Caucasian, African-American, Asian) and four apolipoprotein E phenotype groups (3a3, 3a2, 4a3, and 4a2). Intervention: During the ®rst week the subjects consumed a baseline diet providing 11 energy (en)% saturated fat, 10 en% polyunsaturated fat and 14 en% monounsaturated fat. Followed by test diets with 19 en% saturated fat (including 14 en% test saturated fatty acid), 3 en% polyunsaturated fat, and 14 en% monounsaturated fat for four weeks. Synthetic fats (trimyristin, tripalmitin, and tristearin) were used in blends with natural fats and oils. Results: Mean concentrations of serum total, esteri®ed and LDL cholesterol were signi®cantly lower after 18:0 than after 16:0 (n 16 ± 18, P`0.01 for treatment effect). Myristic acid (14:0) had an intermediate effect.Receptor-mediated degradation of 125 I-LDL in mononuclear cells obtained from the subjects was lower after 16:0 than after 14:0 and 18:0 (n 16 ± 18, P 0.05 for treatment effect). Differences in the digestibilities of the fats were not a major factor in the results. Strong cholesterolemic responses to the 16:0 diet were partly explained by apoE phenotype. Conclusions: As noted previously, stearic acid was neutral compared to 14:0 and 16:0. In contrast to studies involving natural fats, 14:0, fed as a synthetic triglyceride, was less cholesterolemic than 16:0 in a majority of subjects. ApoE phenotype in¯uenced the cholesterolemic response particularly when diets high in 16:0 were eaten.

Two randomized, blind studies measured changes in serum cholesterol, other serum lipids, and apolipoprotein (apo) concentrations in hypercholesterolemic men consuming caprenin (Cap)-rich diets after either baseline diets enriched in palm oil/palm-kernel oil (PO/PKO) or butter. The triglyceride Cap contains 45% 22:0 and 50% 8:0-10:0. Compared with baseline values established at 3 wk on the PO/PKO diet, the 17 subjects on the Cap diet showed significant reductions after 6 wk in HDL cholesterol (HDL-C), HDL2-C, and HDL3-C and a significant increase in the ratio of total cholesterol, LDL-C, triglycerides, apo B-100, or apo A-I were seen. Compared with baseline values established at 3 wk on the butter diet, after 6 wk the seven subjects receiving the Cap diet showed no significant changes in the lipid and apolipoprotein indexes analyzed. These data show that one or more of 8:0, 10:0, and 22:0 fatty acids can contribute to hypercholesterolemia in men.

No abstract

No abstract