Alternative titles; symbols
HGNC Approved Gene Symbol: CTRB1
Cytogenetic location: 16q23.1 Genomic coordinates (GRCh38): 16:75,218,988-75,224,924 (from NCBI)
Alpha-chymotrypsin (EC 3.4.21.1) is one of a family of serine proteases secreted into the gastrointestinal tract as the inactive precursor chymotrypsinogen. The zymogen is activated by proteolytic cleavage by trypsin (PRSS1; 276000).
Tomita et al. (1989) isolated a cDNA clone encoding prechymotrypsinogen from a human pancreas cDNA library and determined its nucleotide sequence. The coding region contains 789 bp. The predicted product consisted of 263 amino acids, including 18 amino acids for a signal peptide. Southern blot analyses using the cloned cDNA as a probe showed that human genomic DNA carries at least 2 genes that are related to chymotrypsinogen.
Sakaguchi et al. (1982) and Honey et al. (1984) assigned the human chymotrypsinogen B gene to chromosome 16 by use of a cloned rat CTRB sequence as probe DNA from human-mouse somatic cell hybrids. Homology indicates that CTRB is on 16q because it is one of 7 genes that are on 16 in man and on chromosome 8 in the mouse (Barton et al., 1986); the other 6 are on 16q, whereas human 16p, which carries the alpha-globin gene cluster, appears to be homologous to mouse 11. Using RFLPs for CTRB, tyrosine aminotransferase (TAT; 613018), and HP, Westphal et al. (1987) analyzed linkage in 13 informative families. TAT and HP are known to reside at 16q22. The most likely order was found to be HP--7 cM--TAT--9 cM--CTRB. By pulsed field gel electrophoresis, a maximum physical distance of about 700 kb was obtained between HP and TAT, which contrasts with the genetic distance of 7 cM (approximate confidence limits, 2-18 cM). The physical distance between TAT and HP is about 10 times shorter than might be expected for a genetic length of 7 cM. On average, one expects 1 cM to correspond to 1,000 kb in the human genome; however, recombination is undoubtedly not uniform. Several instances of increased recombination rate within small regions of the genome are known. Observations in cases of deletion cited by Westphal et al. (1987) suggested that CTRB may be in 16q22.2, telomeric to both HP and TAT. Using a cDNA probe for the rat CTRB gene to analyze 2 overlapping interstitial deletions on human chromosome 16q by Southern blot analysis, Natt et al. (1989) concluded that CTRB lies in the shortest region of overlap, band 16q22.3 (taking other published data into account). Chen et al. (1991) mapped 12 genes and 33 anonymous DNA probes on 16q. They concluded that the CTRB gene lies in band 16q23.2-q23.3.
Barton, D. E., Yang-Feng, T. L., Francke, U. The human tyrosine aminotransferase gene mapped to the long arm of chromosome 16 (region 16q22-q24) by somatic cell hybrid analysis and in situ hybridization. Hum. Genet. 72: 221-224, 1986. [PubMed: 2870017] [Full Text: https://doi.org/10.1007/BF00291881]
Chen, L. Z., Harris, P. C., Apostolou, S., Baker, E., Holman, K., Lane, S. A., Nancarrow, J. K., Whitmore, S. A., Stallings, R. L., Hildebrand, C. E., Richards, R. I., Sutherland, G. R., Callen, D. F. A refined physical map of the long arm of human chromosome 16. Genomics 10: 308-312, 1991. [PubMed: 2071140] [Full Text: https://doi.org/10.1016/0888-7543(91)90313-4]
Honey, N. K., Sakaguchi, A. Y., Quinto, C., MacDonald, R. J., Bell, G. I., Craik, C., Rutter, W. J., Naylor, S. L. Chromosomal assignment of human genes for serine proteases trypsin, chymotrypsin B and elastase. Somat. Cell Molec. Genet. 10: 369-376, 1984. [PubMed: 6589790] [Full Text: https://doi.org/10.1007/BF01535632]
Natt, E., Magenis, R. E., Zimmer, J., Mansouri, A., Scherer, G. Regional assignment of the loci for uvomorulin (UVO) and chymotrypsinogen B (CTRB) with the help of two overlapping deletions on the long arm of chromosome 16. Cytogenet. Cell Genet. 50: 145-148, 1989. [PubMed: 2789125] [Full Text: https://doi.org/10.1159/000132745]
Sakaguchi, A. Y., Naylor, S. L., Quinto, C., Rutter, W. J., Shows, T. B. The chymotrypsinogen B gene (CTRB) is on human chromosome 16. Cytogenet. Cell Genet. 32: 313 only, 1982.
Tomita, N., Izumoto, Y., Horii, A., Doi, S., Yokouchi, H., Ogawa, M., Mori, T., Matsubara, K. Molecular cloning and nucleotide sequence of human pancreatic prechymotrypsinogen cDNA. Biochem. Biophys. Res. Commun. 158: 569-575, 1989. [PubMed: 2917002] [Full Text: https://doi.org/10.1016/s0006-291x(89)80087-7]
Westphal, E.-M., Burmeister, M., Wienker, T. F., Lehrach, H., Bender, K., Scherer, G. Tyrosine aminotransferase and chymotrypsinogen B are linked to haptoglobin on human chromosome 16q: comparison of genetic and physical distances. Genomics 1: 313-319, 1987. [PubMed: 2896626] [Full Text: https://doi.org/10.1016/0888-7543(87)90030-9]