Conversion of Aß43 to Aß40 by the successive action of angiotensin-converting enzyme 2 and angiotensin-converting enzyme.

The longer and neurotoxic species of amyloid-ß protein (Aß), Aß42 and Aß43, contribute to Aß accumulation in Alzheimer's disease (AD) pathogenesis and are considered to be the primary cause of the disease. In contrast, the predominant secreted form of Aß, Aß40, inhibits amyloid deposition and may have neuroprotective effects. We have reported that angiotensin-converting enzyme (ACE) converts Aß42 to Aß40 and that Aß43 is the earliest-depositing Aß species in the amyloid precursor protein transgenic mouse brain. Here we found that Aß43 can be converted to Aß42 and to Aß40 in mouse brain lysate. We further identified the brain Aß43-to-Aß42-converting enzyme as ACE2. The purified human ACE2 converted Aß43 to Aß42, and this activity was inhibited by a specific ACE2 inhibitor, DX600. Notably, the combination of ACE2 and ACE could convert Aß43 to Aß40. Our results indicate that the longer, neurotoxic forms of Aß can be converted to the shorter, less toxic or neuroprotective forms of Aß by ACE2 and ACE. Moreover, we found that ACE2 activity showed a tendency to decrease in the serum of AD patients compared with normal controls, suggesting an association between lower ACE2 activity and AD. Thus, maintaining brain ACE2 and ACE activities may be important for preventing brain amyloid neurotoxicity and deposition in Alzheimer's disease.

A chiral photochromic Schiff base: (R)-4-meth-oxy-2-[(1-phenyl-ethyl)imino-meth-yl]phenol.

The title chiral photochromic Schiff base compound, C(16)H(17)NO(2), was synthesized from (R)-1-phenyl-ethyl-amine and 5-methoxy-salicylaldehyde. The mol-ecule of the title compound exists in the phenol-imine tautomeric form. The dihedral angle between the two aromatic rings is 62.61 (11)°. An intra-molecular O-H⋯N hydrogen bond with an O⋯N distance of 2.589 (2) Šis observed. The crystal packing is stabilized by C-H⋯π inter-actions involving the aromatic ring.

Identification of 779 genetic variations in eight genes encoding members of the ATP-binding cassette, subfamily C (ABCC/MRP/CFTR.

We screened DNAs from 48 Japanese individuals for single-nucleotide polymorphisms (SNPs) in eight genes encoding the ATP-binding cassette, subfamily C (ABCC/ MRP/CFTR), by direct sequencing of their entire genomic regions, except repetitive sequence elements. This approach identified 688 SNPs and 91 insertion/deletion polymorphisms among the eight genes. Of the 688 SNPs, 81 were identified in the ABCC1 gene, 41 in ABCC2, 30 in ABCC3, 230 in ABCC4, 76 in ABCC5, 58 in CFTR, 102 in ABCC8. and 70 in ABCC9. Six SNPs were located in the 5' flanking regions, 617 in introns, 46 in exons, and 19 in the 3' flanking regions. These variants should contribute to studies that investigate possible correlations of genotypes with disease-susceptibility phenotypes and responsiveness or adverse effects to drugs.

Three hundred twenty-six genetic variations in genes encoding nine members of ATP-binding cassette, subfamily B (ABCB/MDR/TAP), in the Japanese population.

We screened DNAs from 48 Japanese individuals for single-nucleotide polymorphisms (SNPs) in nine genes encoding components of ATP-binding cassette subfamily B (ABCB/MDR/TAP) by directly sequencing the entire applicable genomic regions except for repetitive elements. This approach identified 297 SNPs and 29 insertion/deletion polymorphisms among the nine genes. Of the 297 SNPs, 50 were identified in the ABCB1 gene, 14 in TAP], 35 in TAP2, 48 in ABCB4, 13 in ABCB7, 21 in ABCB8, 21 in ABCB9, 13 in ABCB10, and 82 in ABCB11. Thirteen were located in 5' flanking regions, 237 in introns, 37 in exons, and 10 in 3' flanking regions. These variants may contribute to investigations of possible correlations between genotypes and disease-susceptibility phenotypes or responsiveness to drug therapy.