[Clinical characteristics of 170 cases of macrodactyly].

OBJECTIVE: To analyze the clinical characteristics of 170 cases of macrodactyly. METHODS: Medical records of 170 macrodactyly patients at Beijing Jishuitan Hospital between March 2006 and October 2019, including demographic characteristics, clinical presentations, anatomical distributions, X-rays, pathological findings, and treatments, were reviewed. PIK3CA mutation analyses of 12 patients were also reviewed. RESULTS: Disease incidence was similar across sex and geographical regions. Multiple-digit involvement was 3.9 times more frequent than single-digit involvement. In upper deformit: ies, the index finger, middle finger and thumb were mostly involved, and the second and third toes were the most affected on the foot. Two digits were affected more often than three digits, with the affected multiple digits were adjacent most time. The cases of progressive macrodactyly, in which the affected digits grew at a faster rate than the unaffected digits, were found more than static type. Most of progressive macrodactyly were noticed at birth. In terms of nerve involvement, affected fingers mostly occurred in the median nerve innervation area (79.4%) accompanied by median nerve and brunches enlargement and fat infiltration, i.e., nerve territory oriented; affected toes mostly occurred in the medial plantar nerve innervation area (89.1%), marked with overgrowth of adipose tissue with a lesser degree of neural overgrowth, i.e., lipomatous. Only 17 cases had comorbid of syndactyly. The metacarpal bones were involved only in progressive type of macrodactyly. Ten of the 12 cases subjected to PIK3CA mutation analysis were positive. Among all tested specimens, PIK3CA mutation levels ranged from 7% to 27%. In terms of tissue sources in which a mutation was found, adipose tissue had the highest mutation detection rate, followed by nerve and skin. All the DNA samples of blood from the 12 PIK3CA mutation-positive patients were negative. CONCLUSION: Macrodactyly fingers mostly occurred in the median nerve innervation area accompanied by median nerve and brunches enlargement and fat infiltration. The index and middle fingers were mostly involved. Macrodactyly toes mostly occurred in the medial plantar nerve innervation area, marked with overgrowth of adipose tissue with a lesser degree of neural overgrowth. The second and third toes were the most affected on the foot. A high proportion (83%) of isolated macrodactyly patients carry activating PIK3CA mutations. Adipose, nerve, and skin tissues provide the highest PIK3CA mutation detection yield among all types of tissue studied.

[PIK3CA mutation analysis in isolated macrodactyly].

Objective: To systematically investigate PIK3CA mutations in isolated macrodactyly. Methods: Overgrowth tissues from 12 isolated macrodactyly patients who were treated at Department of Hand Surgery, Beijing Jishuitan Hospital from May to August 2017 were collected during operation.There were 6 male and 6 female patients with average age of 4.5 years. DNA was tested for PIK3CA mutation using a targeted Sanger DNA sequencing method.Samples with negative Sanger result were tested with a next generation DNA sequencing(NGS)panel targeting 47 cancer hotspot genes including PIK3CA. Results: By targeted Sanger sequencing, PIK3CA mutations were detected in 9 of the 12 patients, with mutation level ranging from 7% to 27%.The PIK3CA mutations observed were p. His1047Arg, p.His1047Leu, p.Glu545Lys, and p. Glu542Lys.NGS found p. Glu453Lys in one additional patient, allowing the total positive rate to 10/12.All PIK3CA mutations detected in the study were cancer hotspot mutations.Among all tissue types tested, adipose tissue had the highest mutation detection rate(9/9), followed by nerve(10/12) and skin(10/12). Conclusions: A high proportion of isolated macrodactyly patients carry a PIK3CA mutation.Adipose, nerve, and skin are ideal tissue resources for PIK3CA mutation detection.Targeted Sanger sequencing with reflex to NGS represents a cost-effective strategy to test PIK3CA mutations in isolated macrodactyly.

Molecular mapping and candidate gene analysis for resistance to powdery mildew in Cucumis sativus stem.

Powdery mildew (PM) of cucumber (Cucumis sativus), caused by Podosphaera xanthii, is a major foliar disease worldwide and resistance is one of the main objectives in cucumber breeding programs. The resistance to PM in cucumber stem is important to the resistance for the whole plant. In this study, genetic analysis and gene mapping were implemented with cucumber inbred lines NCG-122 (with resistance to PM in the stem) and NCG-121 (with susceptibility in the stem). Genetic analysis showed that resistance to PM in the stem of NCG-122 was qualitative and controlled by a single-recessive nuclear gene (pm-s). Susceptibility was dominant to resistance. In the initial genetic mapping of the pm-s gene, 10 SSR markers were discovered to be linked to pm-s, which was mapped to chromosome 5 (Chr.5) of cucumber. The pm-s gene's closest flanking markers were SSR20486 and SSR06184/SSR13237 with genetic distances of 0.9 and 1.8 cM, respectively. One hundred and fifty-seven pairs of new SSR primers were exploited by the sequence information in the initial mapping region of pm-s. The analysis on the F2 mapping population using the new molecular markers showed that 17 SSR markers were confirmed to be linked to the pm-s gene. The two closest flanking markers, pmSSR27and pmSSR17, were 0.1 and 0.7 cM from pm-s, respectively, confirming the location of this gene on Chr.5. The physical length of the genomic region containing pm-s was 135.7 kb harboring 21 predicted genes. Among these genes, the gene Csa5G623470 annotated as encoding Mlo-related protein was defined as the most probable candidate gene for the pm-s. The results of this study will provide a basis for marker-assisted selection, and make the benefit for the cloning of the resistance gene.

[Arthroscopic management of lesser arc perilunate injuries].

OBJECTIVE: To evaluate the outcomes of lesser arc perilunate injuries (Perilunate dislocations) treated with arthroscopically assisted mini-invasive reduction and fixation. METHODS: Between 2012 and 2014, 5 patients who had a perilunate dislocation were treated with arthroscopically assisted reduction and percutaneous fixation. The mean follow-up was 17.8 months (range, 10 to 32 months). Clinical outcomes were evaluated on the basis of range of motion; grip strength; Mayo wrist score; Quick disabilities of the arm, shoulder and hand questionnaire; and patient-rated wrist evaluation score. Radiographic evaluations included carpal alignments and any development of arthritis. RESULTS: The range of flexion-extension motion of injured wrist averaged 84% of the values for contralateral wrist. The grip strength of the injured wrist averaged 90% of the values for the contralateral wrists. The mean Quick Disabilities of the arm, shoulder and hand score was 1, and the mean Patient-Rated Wrist Evaluation score was 5. According to the Mayo wrist scores, the overall functional outcomes were rated as excellent in all the patients. Reduction obtained during the operation was maintained within normal ranges in all the patients. Arthritis had not developed in any patient at the end of the follow-up. CONCLUSION: Arthroscopic mini-invasive reduction with percutaneous fixation is a reliable and favorable alternative in the treatment of perilunate dislocations according to our early results.

[Application of a microvascular anastomotic coupling device in solitary upper extremity artery injury repairs].

OBJECTIVE: To investigate the outcomes of applying microvascular anastomotic coupling devices in solitary upper extremity artery injury repairs and to optimize parameters for optimal clinical outcome. METHODS: From March to September 2013, 19 injured arteries from 18 male patients who presented at Department of Hand Surgery, Beijing Jishuitan Hospital with traumatic arterial lacerations of their upper extremities went through rapid repair procedures. COUPLER, a microvascular anastomotic coupling device was applied in these artery injury repair operations. The 19 repaired arteries included 3 brachial arteries, 6 ulnar arteries and 10 radial arteries. After the procedures, all the 18 patients were then followed up by clinical specialists and examined with color doppler flow imaging for the effective recovery of artery circulation and upper extremities functionality. RESULTS: The average time of artery repairs for all the 19 damaged arteries among the 18 patients was 278 s and the average follow-up time was (71.5±40.9) d with the longest follow-up time as 116 d and shortest as 14 d. No patient returned to the operating room after the procedures and after being dismissed from the hospital. None of the 18 cases were reported to have problems with circulation and thrombosis formation in their upper extremities. Color Doppler imaging showed that the arterial anastomotic site for all the 19 repaired arteries were unobstructed with artery blood spectrum at both ends. Three patients with radial artery repairs complained about mild pressure pain at the site of vascular anastomosis; while the other 15 patients all expressed satisfactory outcomes of the surgery and recovery. These evidences indicated that the outcomes of our initial evaluation for the solitary upper extremity artery injury repairs by using anastomotic coupling devices were positive. CONCLUSION: Our observations have showed that microvascular anastomotic coupling devices can be used for repairing of solitary upper extremity artery injures. The procedures are quick, effective and safe. The clinical application of this microvascular anastomotic coupling device in artery injures is promising, however, additional evidences through further clinical investigation with more cases are warranted.

[Role and prospect of regenerative medicine in early treatment of combat trauma].

The regenerative medicine has made great breakthrough in the repair of combat trauma, showing broad prospects, while the method of regenerative medicine applied in the early treatment of combat trauma is not yet clear. The early treatment of combat trauma includes strict control of bleeding, a large amount of blood transfusion, alleviation of acidosis, and correction of hypothermia and improvement of coagulation dysfunction, etc. This paper focuses on the bio-engineered blood, research and development of homeostatic materials, control of inflammation/infection, regulation of immunity, protection of important organs, establishment of military medical model, research and development of biosensors and drugs, and preventive application of stem cell bank in regenerative and tissue engineering in defense medicine to summarize the role of regenerative medicine in the early treatment of combat trauma, hoping to improve the overall treatment level of combat trauma.

[Establishment of an auxiliary diagnosis system of newborn screening for inherited metabolic diseases based on artificial intelligence technology and a clinical trial].

Objective: To establish a disease risk prediction model for the newborn screening system of inherited metabolic diseases by artificial intelligence technology. Methods: This was a retrospectively study. Newborn screening data (n=5 907 547) from February 2010 to May 2019 from 31 hospitals in China and verified data (n=3 028) from 34 hospitals of the same period were collected to establish the artificial intelligence model for the prediction of inherited metabolic diseases in neonates. The validity of the artificial intelligence disease risk prediction model was verified by 360 814 newborns' screening data from January 2018 to September 2018 through a single-blind experiment. The effectiveness of the artificial intelligence disease risk prediction model was verified by comparing the detection rate of clinically confirmed cases, the positive rate of initial screening and the positive predictive value between the clinicians and the artificial intelligence prediction model of inherited metabolic diseases. Results: A total of 3 665 697 newborns' screening data were collected including 3 019 cases' positive data to establish the 16 artificial intelligence models for 32 inherited metabolic diseases. The single-blind experiment (n=360 814) showed that 45 clinically diagnosed infants were detected by both artificial intelligence model and clinicians. A total of 2 684 cases were positive in tandem mass spectrometry screening and 1 694 cases were with high risk in artificial intelligence prediction model of inherited metabolic diseases, with the positive rates of tandem 0.74% (2 684/360 814)and 0.46% (1 694/360 814), respectively. Compared to clinicians, the positive rate of newborns was reduced by 36.89% (990/2 684) after the application of the artificial intelligence model, and the positive predictive values of clinicians and artificial intelligence prediction model of inherited metabolic diseases were 1.68% (45/2 684) and 2.66% (45/1 694) respectively. Conclusion: An accurate, fast, and the lower false positive rate auxiliary diagnosis system for neonatal inherited metabolic diseases by artificial intelligence technology has been established, which may have an important clinical value.

MicroRNA-29 targets FGF2 and inhibits the proliferation, migration and invasion of nasopharyngeal carcinoma cells via PI3K/AKT signaling pathway.

The article "MicroRNA-29 targets FGF2 and inhibits the proliferation, migration and invasion of nasopharyngeal carcinoma cells via PI3K/AKT signaling pathway, by M. Xu, G.-L. Tian, C.-C. Hao, M. Shi, D.-J. Zha, K. Liang, published in Eur Rev Med Pharmacol Sci 2019; 23 (12): 5215-5222. DOI: 10.26355/eurrev_201906_18186. PMID: 31298371" has been withdrawn from the authors. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/18186.

MicroRNA-29 targets FGF2 and inhibits the proliferation, migration and invasion of nasopharyngeal carcinoma cells via PI3K/AKT signaling pathway.

OBJECTIVE: Studies have indicated that miRNAs may prove essential therapeutic targets for the treatment of cancer. The study was designed to investigate the role and therapeutic potential of miR-29 in nasopharyngeal cancer. MATERIALS AND METHODS: The quantitative Real-time polymerase chain reaction (qRT-PCR) was used for expression analysis. WST-1 assay was used for cell viability assessment. The 4',6-diamidino-2-phenylindole (DAPI) staining and electron microscopic analysis was used for the detection of apoptosis and autophagy, respectively. Transwell assays were used for cell migration and invasion assay. RESULTS: It was found that miR-29 is significantly downregulated in nasopharyngeal cancer cell lines. Overexpression of miR-29 causes decrease in the viability of CNE2 nasopharyngeal cancer cells via induction of apoptosis and autophagy. Bioinformatics analysis indicated FGF2 to be the target of miR-29 in CNE2 cells, which was also confirmed by luciferase reporter assay. The qRT-PCR results showed fibroblast growth factor 2 (FGF2) to be significantly upregulated in the nasopharyngeal cancer cell lines. However, miR-29 overexpression in CNE2 cells resulted in post-transcriptional suppression of FGF2 expression. Nonetheless, silencing of FGF2 also caused inhibition of CNE2 cell proliferation via induction of apoptosis and autophagy. Overexpression of FGF2 could reverse the effects of miR-29 overexpression on the proliferation of CNE2 cells. Moreover, overexpression of miR-29 causes significant decline in the phosphorylation of PI3K and AKT expression cells and inhibits their migration and invasion of the CNE2 cells. Finally, miR-29 overexpression could also suppress the subcutaneous xenografted tumor growth. CONCLUSIONS: The findings of the present study indicate the therapeutic implications of miR-29 in nasopharyngeal carcinoma.

Pioglitazone improves the ability of learning and memory via activating ERK1/2 signaling pathway in the hippocampus of T2DM rats.

OBJECTIVE: To explore the correlation between effect of PIO (pioglitazone, PIO) on learning as well as memory and ERK1/2 (extracellular signal regulated kinase 1/2, ERK1/2) pathway in T2DM (type 2 diabetes mellitus, T2DM) rats, further to elucidate the potential mechanism of PIO in improvement of learning and memory. METHODS: 12-week-old male SD rats (number of 10 per group) were randomly divided into control group (CON), T2DM group (DM) and T2DM +PIO group (DM+PG). Rats in DM and DM+PG groups were given high fat diet for 20 weeks, then treated with Streptozotocin (27mg/kg) by intraperitoneal injection at 21week. After 72h, the FBG (fasting blood glucose, FBG) was greater than 7.0mmol/L can considered T2DM rats. DM+PG group was treated with PIO (10 mg·kg-1·d-1) by gavage daily. After Hyperinsulinemic-Euglycemic Clamp Study and Morris water maze test at 30-week, all of animals were sacrificed. The expressions of RKIP (Raf-1 kinase inhibitor protein, RKIP) and ERK1/2 in hippocampus were detected using Western Blot and real-time PCR. RESULTS: The FBG level: DM group (7.68±0.54mmol/L) was higher than CON group (5.35±0.63mmol/L) and DM+PG group (6.07±0.84mmol/L), the differences were considered statistically significant (P <0.05). Hyperinsulinemic-Euglycemic Clamp Studies: GIR (glucose infusion rate, GIR) of DM group (21.02±5.10 mg·kg-1·d-1) was less than CON group (27.64±3.87 mg·kg-1·d-1) and DM+PG group (26.04 ±5.41 mg·kg-1·d-1), the differences were considered statistically significant (P <0.05). Morris water maze training: The escape latencies and searching platform performance of DM group (24.54±5.02s) decreased significantly compared with CON group (16.73±4.02s) and DM+PG group (18.05±4.12s) (P <0.05). Changes of RKIP, ERK, p-ERK protein relative content in rat hippocampus: Compared with CON groupand DM+PG group, the relative content of RKIP in DM group remarkably increased (P<0.01); ERK protein levels were not considered statistically significant among the three groups (P>0.05); The relative content of p-ERK1/2 protein in CON group and DM+PG group rats dorsal were higher than those in group DM, the difference was considered statistically significant (P<0.01). Changes in hippocampus of rat RKIP and ERK gene relative content: Compared with CON group and DM+PG group, levels of RKIP mRNA in DM group were significantly increased (P<0.01); ERK mRNA levels were not considered statistically significant among the three groups (P>0.05). CONCLUSION: Activation of ERK1/2 signal transduction pathway via reducing RKIP in the hippocampus may be one of the mechanisms of PIO to improve the learning and memory of the T2DM rats.

Incipient mitochondrial evolution in yeasts. II. The complete sequence of the gene coding for cytochrome b in Saccharomyces douglasii reveals the presence of both new and conserved introns and discloses major differences in the fixation of mutations in evolution.

We have determined the complete sequence of the mitochondrial gene coding for cytochrome b in Saccharomyces douglasii. The gene is 6310 base-pairs long and is interrupted by four introns. The first one (1311 base-pairs) belongs to the group ID of secondary structure, contains a fragment open reading frame with a characteristic GIY ... YIG motif, is absent from Saccharomyces cerevisiae and is inserted in the same site in which introns 1 and 2 are inserted in Neurospora crassa and Podospora anserina, respectively. The next three S. douglasii introns are homologous to the first three introns of S. cerevisiae, are inserted at the same positions and display various degrees of similarity ranging from an almost complete identity (intron 2 and 4) to a moderate one (intron 3). We have compared secondary structures of intron RNAs, and nucleotide and amino acid sequences of cytochrome b exons and intron open reading frames in the two Saccharomyces species. The rules that govern fixation of mutations in exon and intron open reading frames are different: the relative proportion of mutations occurring in synonymous codons is low in some introns and high in exons. The overall frequency of mutations in cytochrome b exons is much smaller than in nuclear genes of yeasts, contrary to what has been found in vertebrates, where mitochondrial mutations are more frequent. The divergence of the cytochrome b gene is modular: various parts of the gene have changed with a different mode and tempo of evolution.

Incipient mitochondrial evolution in yeasts. I. The physical map and gene order of Saccharomyces douglasii mitochondrial DNA discloses a translocation of a segment of 15,000 base-pairs and the presence of new introns in comparison with Saccharomyces cerevisiae.

We have determined the physical and genetic map of the 73,000 base-pair mitochondrial genome of a novel yeast species Saccharomyces douglasii. Most of the protein and RNA-coding genes known to be present in the mitochondrial DNA of Saccharomyces cerevisiae have been identified and located on the S. douglasii mitochondrial genome. The nuclear genomes of the two species are thought to have diverged some 50 to 80 million years ago and their nucleo-mitochondrial hybrids are viable but respiratorily deficient. The mitochondrial genome of S. douglasii displays many interesting features in comparison with that of S. cerevisiae. The three mosaic genes present in both genomes are quite different with regard to their structure. The S. douglasii COXI gene has two new introns and is missing the five introns of the S. cerevisiae gene. The S. douglasii cytochrome b gene has one new intron and lacks two introns of the S. cerevisiae gene. Finally, the L-rRNA gene of S. douglasii, like that of S. cerevisiae, has one intron of which the structure is different. Another salient feature of the S. douglasii mitochondrial genome reported here is that the gene order is different in comparison with S. cerevisiae mitochondrial DNA. In particular, a segment of approximately 15,000 base-pairs including the genes coding for COXIII and S-rRNA has been translocated to a position between the genes coding for varl and L-rRNA.

Sequence of the mitochondrial gene encoding subunit I of cytochrome oxidase in Saccharomyces douglasii.

We have determined the complete sequence of the mitochondrial (mt) gene (COXI) coding for cytochrome oxidase subunit I of Saccharomyces douglasii. This gene is 7238 bp long and includes four introns. The salient feature of the S. douglasii COXI gene is the presence of two introns, Sd.ai1 and Sd.ai2, which have not been observed in S. cerevisiae genes. Both are group-I introns and are located at novel positions compared with the S. cerevisiae COXI. Interestingly, one of these introns (the second one) is inserted at the same position as intron 2 of COXI of Kluyveromyces lactis and also as intron 8 of the same gene in Podospora anserina. The ORFs contained in these three introns display a high degree of similarity. Comparisons of exonic and intronic sequences of the COXI of two Saccharomyces species reinforces our previous conclusions: the evolution of mt genes in yeast obeys different rules to those found in vertebrates.

Congenital perforation of the triangular fibrocartilage of the wrist.

The triangular fibrocartilages (TFC) of 136 wrist joints from 48 fetuses and 20 infants fresh cadavers without any evidence of known deformity and injury were studied. Perforations of the TFC were found not only in infants (18.8%), but also in fetuses (25%). The difference between the incidences of the perforations in the two groups is not statistically significant (P > 0.05). Furthermore, we did not find that perforation of the TFC is correlated with either sex or side of wrists (P > 0.05). Histologically, the vascularity and cellularity of the TFC have no significant correlation with the absence or presence of perforation in it. We believe that, besides trauma, inflammation and degeneration, some perforations of the TFCs are congenital in origin, which all take the form of fissure and are located mainly in the radial half of the TFC.

[Congenital perforation of the triangular fibrocartilage of the wrist].

The authors dissected 136 wrist joints from fetus and infant fresh cadavers. The perforation rates of the triangular fibrocartilage of the wrist in these two groups were found to be 18.8% and 25%, respectively. The authors believe that, besides traumatic, inflammatory and degenerative causes, some perforations are congenital in origin. They are not found to be correlated with either sex or side of wrists (P > 0.05).

[Clinical evaluation of blood supply of the hand].

The blood supply of 39 apparently normal hands was examined by the use of the Allen test and a Doppler Ultrasonic Blood Flow Detector. The ultrasonic examination appears to be more sensitive to the change of blood supply to the hand than the Allen test and to have higher degree of accuracy. The Allen test seems to provide some useful information, but it is a relatively crude test. The ultrasonic examination should become one of the routine examinations of patients who are likely to undergo procedures which may interfere with the normal circulation of the hand.

The length and position of the long axis of the scaphoid measured by analysis of three-dimensional reconstructions of computed tomography images.

We established the maximum length and the position of the long axis of the scaphoid from three-dimensional reconstructions of spiral computed tomography in 30 pairs of wrists. The distance between two points on the three-dimensional scaphoid surface model were calculated using commercially available software and corresponding coordinates of the two points were documented. The mean length was 29.3 (SD 1.6) mm for men and 26.6 (SD 1.8) mm for women. The location of the distal point was at the centre of the scaphoid tuberosity, with the proximal point of the long axis located at the dorsal ridge of the scapholunate facet.

Synthesis of dermorphin-(1-4) derivatives catalyzed by proteases in organic solvents.

In order to extend the use of proteases to organic synthesis and seek the rules of enzymatic reactions in organic media, we focused on unnatural substrates for proteases to form amide bonds. In this paper, the study of unnatural substrates containing D-amino acid residue, which act as acyl acceptors as well as acyl donors for proteases in organic media, is reported. Dermorphin is a heptapeptide (H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH(2)) with potent analgesic activity. The N-terminal tetrapeptide is the minimum sequence that retains dermorphin activity, and is selected as the model compound in our study. Two dermorphin-(1-4) derivatives, Boc-Tyr-D-Ala-Phe-Gly-N(2)H(2)Ph and Boc-Tyr-D-Ala-Phe-Gly-NH(2), which contained a d-amino acid residue, were synthesized by proteases in organic media for the first time. The synthesis of these two dermorphin-(1-4) derivatives could be catalyzed by subtilisin with Boc-Tyr-D-Ala-OCH(2)CF(3) as an acyl donor substrate in AcOEt. The synthesis of dermorphin-(1-2) derivative Boc-Tyr-D-Ala-N(2)H(2)Ph was catalyzed by alpha-chymotrypsin in different organic solvents and D-Ala-N(2)H(2)Ph was used as an acyl acceptor substrate. Factors influencing the above enzymatic reactions were systematically studied.

Influence of reaction conditions on syntheses of sweetener precursors catalyzed by thermolysin in tert-amyl alcohol.

The activity of enzymes to form a peptide bond in organic solvent was greatly influenced by observed pH and water content. The precursors of two sweeteners, P-Asp-Xaa-OR (P=Z or For, Xaa-OR=Phe-OMe or Ala-OcHex), were synthesized by enzyme, and the reaction conditions were studied systematically. Z-Asp-OH was coupled with H-Phe-OMe or H-Ala-OcHex by thermolysin in tert-amyl alcohol. The best coupling results were obtained when the optimized observed pH was 8 or 9, and the water content was about 6% (V/V). The protecting group Z is better than For under the reaction conditions and H-Phe-OMe is a better nucleophile than H-Ala-OcHex. The expected optically pure peptides were obtained when the racemic amino acids were used as amino components in the starting materials. The physical constants of P-Asp-Xaa-OR synthesized by thermolysin are identical with those of peptides synthesized by chemical method.