l-tryptophan-histidine synthesis by Pseudomonas serine peptidase, an amino acid ester hydrolase of the peptidase family S9.

Pseudomonas sp. KM1 produces an amino acid ester hydrolase (KM1AEH) that catalyzes peptide bond formation by acting on carboxylic ester bonds. The KM1AEH gene was cloned from genomic DNA and expressed in Escherichia coli. The recombinant enzyme (rKM1AEH) was purified, and gel filtration showed that it is a 68 kDa monomeric protein. rKM1AEH can synthesize the vasoactive dipeptide tryptophan-histidine from tryptophan methyl ester and histidine as acyl donor and acceptor, respectively. The enzyme showed maximum activity at pH 9.5 and 45 °C and was specifically inhibited by silver (Ag+). Mutation of the catalytic Ser459 residue in the active site of rKM1AEH with Ala, Cys, or Thr eliminated all catalytic activity. The enzyme is a novel ester hydrolase that belongs to the peptidase family S9 based on the phylogenetic analysis.

Carcinoma in a solitary intraductal papilloma of the breast.

Herein is reported a rare case of carcinoma arising from papilloma of the breast. A 63-year-old postmenopausal woman noticed a nodule approximately 1 cm in diameter in her left breast. Ultrasonography indicated a mass with a solid pattern within an intracystic tumor measuring 1.5 x 1.5 x 1.4 cm in diameter located near the left nipple. On total image analysis malignancy could not be denied, therefore lumpectomy with resection of the surrounding tissue was performed. Histologically the tumor consisted of cancerous and papilloma components. The cancer cells had high-grade nuclear atypia, were irregular, and contained abundant eosinophilic cytoplasm with a thin vascular stalk. In contrast, the tumor cells had no atypia, and had a thick stroma in the papilloma components. Both lesions could be distinguished clearly from each other. In addition, a transition from papillary to cancerous elements in some areas was seen. An additional partial mastectomy was performed after the lumpectomy but no carcinoma foci were noted in the excised tissue. Possible occurrence of cancerous change in solitary intraductal papilloma of the breast was suspected.

[A case of unknown primary cancer responding to TS-1].

A 65-year-old male showed elevated tumor marker and intra-abdominal lymph node (LN) swelling. PET revealed an accumulation of FDG at para-aortic LNs from the mediastinum to the inguinal region. Although many different examinations were performed to detect primary cancer, none was found. We diagnosed unknown primary cancer (UPC), and administered TS-1 (100 mg/day). Six months later, the tumor marker lowered and the LN swelling reduced. PET showed a little accumulation of FDG at intra-abdominal LN. An intra-abdominal LN biopsy was performed, and an adenocarcinoma was seen at a lymph vessel. Then, 15 months later, brain metastasis was recognized and 18 months later the patient died of systematic metastasis. Autopsy was not performed, and primary cancer was not seen till the end. TS-1 proved effective for the UPC.