International Journal of Analytical Bio-Science Int J Anal Bio-Sci Vol. 2, No 4 (2014) estimate of EE. An important advantage of using HR 〈Original Article〉 over motion sensors is that HR monitoring provides an References index of both the relative (%VO2R), as well as the １ Janz KF: Validation of the CSA accelerometer for absolute intensity (METS) of the physical activity assessing childrenﾕs physical activity. Med Sci Sports Exerc, 26: 369-375, 1994. performed. The importance of relative intensity can be ２ Montoye HJ, Kemper HCG, Saris WHM, et al.: Structural comparison of creatinases for seen when classifying different individuals on the Measuring Physical Activity and Energy Expenditure. investigating substrate binding basis of exercise intensity. Champaign, IL: Human kinetics, pp3-102, 1996. The Karvonen formula determines target HR as ３ Eston RG, Rowlands AV, Ingledew DK: Validity of follows: target HR = (maximum HR － resting HR) heart rate, pedometry, and accelerometry for predicting Yoshiaki Nishiya × ％HRR ＋ resting HR. The American College of the energy cost of children's activities. J Appl Physiol, Sports Medicine categorizes exercise intensity as 84: 362-37, 1998. ４ Rodahl K, Vokac Z, Fugelli P, et al.: Circulatory strain, Summary For further understanding the substrate binding of creatinase, the kinetic parameters of follows based on %VO2R or %HR: very light, <20%; estimated energy output and catecholamine excretion in seven known enzymes and the tertiary structures of more significant ones of those were compared. light, 20-39%; moderate, 40-59%; hard, 60-84%; very Norwegian coastal fishermen. Ergonomics, 17: 585- Used structures were constructed by homology modeling based on the X-ray structure of the enzyme hard, ≧85%; maximum, 100%. 602, 1974. from Pseudomonas putida. The structural comparison of these creatinases showed that the specific In the preset study, there was a tendency that ５ Treiber FA, Musante L, Hartdagan S, et al.: Validation residues in the N-terminal domain, rather than the C-terminal catalytic domain, had influenced on in measured EE was greater than estimated EE calculated of a heart rate monitor with children in laboratory and using the estimation formula, although, a favorable field setting. Med Sci Sports Exerc, 21: 338-342, 1989. the substrate affinity. This result would be assistance in the improvement of creatinase for creatinine correlation was found between measured EE and ６ Washburn RA, Montoye HJ: Reliability of the heart rate and creatine determinations. estimated EE (R2=0.99), supporting the study result of as a measure of mean daily energy expenditure. Exerc Scott et al.12 If the regression equation is employed as Physiol, 2: 161-172, 1986. ７ Goldsmith R, Miller DS, Mumford P, et al.: The use of Key words: Creatinase, Tertiary structure, Homology modeling, Substrate affinity, a correction method, physical activity intensity can be long-term measurements of heart rate to assess energy Creatinine assay calculated from HR and METs; the assessments based expenditure. J Physiol, 189(2): 61-62, 1967. on expensive calculation apparatus and the complexity ８ Washburn RA, Montoye HJ: Reliability of the heart rate of the technique required for accurate measurements of response to submaximal upper and lower body exercise. VO2 are not necessary. The result of this study Res Q Exerc Sports, 56: 166-169, 1985. suggested that the estimation formula would provide ９ Swain DP, Leutholtz BC: Heart rate reserve is equiva- 1. Introduction enzymes for creatinine determination, creatininase and sarcosine oxidase have been already studied and appropriate EE in individual physical activity. lent to %VO2 reserve, not to %VO2max. Med Sci Sports Exsec, 29: 410-414, 1997. Creatinase (creatine amidinohydrolase, EC 3.5.3.3) improved by using protein engineering techniques 10 Swain DP, Leutholtz BC, King ME, et al.: Relationship 14-16 Conclusion catalyses the hydrolyzation of creatine to sarcosine and on the basis of tertiary-structural analysis . In between % heart rate reserve and % VO2 reserve in Actual EE and estimated EE were derived from urea. It is involved in the bacterial metabolism of contrast, the structure-based improvement of creatinase treadmill exercise. Med Sci Sports Exerc, 30: 318-321, creatinine with the related enzymes1. The enzyme is still has not progressed. HR and VO2 while healthy and young subjects 1998 commercially used in the diagnostic analysis of creati- This report shows the tertiary structures of creati- performing various physical activities. Further inves- 11 Davis JA, Convertino VA: A comparison of heart rate nine and creatine with coupling of related enzymes2, 3. nases constructed by homology modeling. Comparison tigation and data collection including larger study methods for predicting endurance training intensity. population are required for the more detailed and Med Sci Sports, 7: 295-298, 1975. Several creatinases have been found, produced, and of these structures indicated that the N-terminal 4-10 clinical evaluation. 12 Strath SJ, Swartz AM, Bassett DR Jr. et al.: Evaluation proved useful in the enzymatic assays . However, the domain, rather than the C-terminal catalytic domain, of heart rate as a method for assessing moderate enzymatic properties of these enzymes are not yet was important for the substrate affinity. This provides intensity physical activity. Med Sci Sports Exerc, 32 (9 Acknowledgement discussed from the viewpoint of tertiary-structural a reasonable starting point for analyzing the structure- suppl): S465-470, 2000. The author thanks Shohei Ichikawa, Takuya comparison, although the X-ray structures of the function relationships and improving the enzyme 13 Karvonen J, Kertala K, Muatala O: The effects of enzymes from Pseudomonas putida and Actinobacillus properties. Katayama, Naoko Shimakura, and Mami Nakazawa in training heart rate: a longitudinal study. Ann Med Exp sp. have already been solved11-13. With respect to the the Department of Health Sciences, Saitama Biochem, 35: 307-315, 1957. Prefectural University, who volunteered to partic- 14 Jackson AS, Blair SN, Mahar MT, et al.: Prediction of Department of Life Science, Faculty of Science and Received for Publication August 27, 2014 ipate in this study. This study was supported by a functional aerobic capacity without exersice testing. Engineering, Setsunan University, Accepted for Publication October 15, 2014 grant from Saitama Prefectural University. Med Sci Sports Exerc, 22: 863-870, 1990. 17-8 Ikeda-Nakamachi, Neyagawa, Osaka 572-8508, Japan E-mail: [email protected] － 142 － － 143 － International Journal of Analytical Bio-Science 2. Materials and methods used for molecular visualization. Homology search analysis of the amino acid 3. Results and discussion sequences of several creatinases was performed using the software GENETYX (Software Development Co., In previous studies, several creatinases from seven Ltd., Tokyo, Japan). The sequences used in this study different genera have been reported with their are in the DDBJ database under accession numbers enzymatic properties4-10. The enzymes from E17219, D00656, D14463, E16405, and BD342394, Arthrobacter, Flavobacterium, Bacillus, Actinobacillus, and in the UniProt ID: P38488. Homology modeling Alcaligenes, Erwinia, and Pseudomonas were desig- was used to build the models of creatinases. The nated CreA, CreF, CreB, CreC, CreL, CreE, and CreP, three-dimensional protein models were generated by respectively. The kinetic parameters and assay condi- the software MODELLER17, based on the structure of tions of these creatinases are compared in Table 1. The P. putida (PDB ID: 1chm). The program Pymol was parameters of CreP and CreE could not be compared Table 1 Comparison of kinetic parameters and assay conditions Creatinase Km (mmol/L) Vmax (U/mg) Assay codition Reference CreA 46 21 37℃ pH 7.6 4 CreF 40 11.3 37℃ pH 7.7 5 CreB NF 10.3 37℃ pH 7.5 6 CreC 19 18.1 37℃ pH 7.5 7 CreL 15.2 19.5 37℃ pH 7.6 8 CreP 14.3 15.0 25℃ pH 7.8 9 CreE 4.2 7.8 25℃ pH 7.8 10 CreA, CreF, CreB, CreC, CreL, CreP, and CreE are from Arthrobacter, Flavobacterium, Bacillus, Actinobacillus, Alcaligenes, Pseudomonas, and Erwinia, respectively. NF; Data not found. Fig. 1 Homology search of amino acid sequences of creatinases. Total sequences and N-terminal domains were compared, and each identity was indicated by a percentage. The CreC sequence was not compared because it was incomplete. － 144 － International Journal of Analytical Bio-Science Int J Anal Bio-Sci Vol. 2, No 4 (2014) 2. Materials and methods used for molecular visualization. with those of others because they were assayed at mean square deviation (RMSD) of atomic Cα the different reaction temperature. Generally, Km and positions of 0.14-0.34Å. Creatinase molecule is Homology search analysis of the amino acid 3. Results and discussion Vmax values are decreased at low temperatures. The Km composed of the two identical subunits, which are sequences of several creatinases was performed using value of CreL was smaller than those of CreA, CreF, designated subunit A and B. Two active sites are the software GENETYX (Software Development Co., In previous studies, several creatinases from seven and CreC, i. e., its binding affinity was higher for formed from the C-terminal catalytic domain of Ltd., Tokyo, Japan). The sequences used in this study different genera have been reported with their creatine. On the other hand, the Km of CreE was much subunit A (or subunit B) and the N-terminal domain of are in the DDBJ database under accession numbers enzymatic properties4-10. The enzymes from smaller than that of CreP. Of all known creatinases, subunit B (or subunit A). For the purpose of discussing E17219, D00656, D14463, E16405, and BD342394, Arthrobacter, Flavobacterium, Bacillus, Actinobacillus, CreL and CreE are practical for diagnostic use because the interaction of creatinase with substrate, the active and in the UniProt ID: P38488. Homology modeling Alcaligenes, Erwinia, and Pseudomonas were desig- of their superior substrate-binding abilities.