Choh Hao Li (sometimes Cho Hao Li) (Chinese: 李卓皓; pinyin: Lǐ Zhuōhào; April 21, 1913 – November 28, 1987) was a Chinese-born American biochemist who discovered in 1966 that human pituitary growth hormone (somatotropin) consists of a chain of 256 amino acids. In 1970, he succeeded in synthesizing this hormone, the largest protein moleculesynthesized up to that time.
Li was born in Guangzhou and educated at the Nanjing University. In 1935, he immigrated to the US, where he took up postgraduate studies at the University of California, Berkeley and later joined the staff. He became professor in 1950. He served as Director of the Hormone Research Laboratory at Berkeley from 1950 to 1967 and at UCSF from 1967 until his retirement in 1983. In 1955, he was elected as Academician of Academia Sinica, Republic of China.
Li spent his entire academic career studying the pituitary-gland hormones. In collaboration with various co-workers, he isolated several protein hormones, including adrenocorticotropic hormone (ACTH),[1] which stimulates the adrenal cortex to increase its secretion of corticoids. In 1956, Li and his group showed that ACTH consists of 39 amino acids arranged in a specific order, and that the whole chain of the natural hormone is not necessary for its action.[2] He isolated another pituitary hormone called melanocyte-stimulating hormone (MSH)[3] and found that not only does this hormone produce some effects similar to those produced by ACTH, but also that part of the amino acid chain of MSH is the same as that of ACTH.
In 1940, Li successfully purified the luteinizing hormone from sheep pituitary glands.[4] The whole process included grinding thousands of glands, extracting the hormone, and then identifying its chemistry and biology at the molecular level.[5] This was a breakthrough in biological studies.
Eight of the nine hormones secreted by the anterior pituitary were isolated and identified by Li and his research team. These nine hormones can be divided into three groups based on the similarity of their chemical properties and biological activities.
1953 - Li was the first person to isolate and extract ACTH.[1]
1964 - Li and his research team discovered and isolated lipotropin, and its structure was defined in 1965.[6]
1975 - Li discovered β-endorphin when trying to find β-lipotropin in camel brain. The team isolated human β-endorphin in 1976 and synthesized it to study its biological activity after they defined the structure of β-endorphin.[7]
1974 - Li and his team sequenced human LH and TSH.[citation needed]
The third group includes growth hormone and prolactin.
1944 - Li was the first person to isolate growth hormone from cow brains.[8] The lack of function of cow growth hormone on human body motivated Dr. Li to find human growth hormone.
1956 - Li successfully isolated human and monkey growth hormone and demonstrated its efficacy to treat hypopituitary children.[9]
1969 - Li discovered the complete primary structure of sheep prolactin.[10]
Li was an expert in diversified areas, including endocrinology, biochemistry, and peptide synthesis. He not only was a widely recognized leader in pituitary-secreted research for his contribution in hormone and growth factors, but also greatly advanced the field of protein chemistry. All of his research had direct impact on clinical applications, especially in growth and fertility. It is estimated that he had published more than 1,000 research papers and had collaborated with more than 300 people. In addition, he was also the recipient of a lot of honors (more than 25). The most significant ones are as follows:
The Establishment of Institute of Biological Chemistry, Academia Sinica[edit]
Despite his significant scientific achievements, Dr. Li was also dedicated to the initiation and development of protein research in Taiwan. In spring 1958, Dr. Li was invited by Dr. Shih Hu to lecture a three-week course regarding the newly developed technology in protein chemistry and his latest pituitary gland research at National Taiwan University with the support from China Foundation for the Promotion of Education and Culture. At that time, the academic community only knew that protein research was developing rapidly abroad and a scholar had already made extraordinary achievements, and so when Dr. Li introduced the first-hand knowledge, it really attracted and inspired domestic scientists. Dr. Li believed that the protein chemistry was the foundation of future biochemical and biological sciences research, so he decided to assist the establishment of domestic protein research institute. In order to cultivate talents in Taiwan, Dr. Li personally provided scholarships and selected and persuaded scholars who have settled in Taiwan to continue the research in his or other research institutes. With the support from Academia Sinica, National Science Council, Ministry of Education, and National Taiwan University, Institute of Biological Chemistry and Institute of Biochemical Sciences, College of Life Science, National Taiwan University were established in 1972. The two institutes were originally located in the National Taiwan University's campus (Institutes of Biological Chemistry moved to Academia Sinica's campus later) to integrate research institutes and the University. Dr. Li had always been serving the chief consultant to assist the collaboration of the two institutes and international networking. The achievement of the two institutes today are built on Dr. Li's hard work. Dr. Li's foresight also brought about the domestic development of biotechnology and genetic engineering.
^Geschwind II, Li CH, Barnafi L (1956). "Isolation and structure of melanocyte-stimulating hormone from porcine pituitary glands". J. Amer. Chem. Soc. 78 (17): 4494–4495. doi:10.1021/ja01598a085.
^Li, C.H.; Simpson, M. E.; Evans, H. M. (1940). "Interstitial cell stimulating hormone. II. Method of preparation and some physico-chemical studies". Endocrinology. 27 (5): 803–808. doi:10.1210/endo-27-5-803.
^Li, C. H. (1956). "Hormones of the Anterior Pituitary Gland. Part I. Growth and Adrenocorticotropic Hormones". Hormones of the anterior pituitary gland. I. Growth and adrenocorticotropic hormones. Advances in Protein Chemistry. Vol. 11. pp. 101–190. doi:10.1016/S0065-3233(08)60421-0. ISBN9780120342112. PMID13469637. {{cite book}}: |journal= ignored (help)
Cole, R D (1996), "Choh Hao Li: April 21, 1913 - November 28, 1987", Biographical Memoirs of the National Academy of Sciences, vol. 70, pp. 221–39, PMID11619324
Hruby, Victor J.; Yamashiro, Donald (1988), "Memorial issue in honor of Professor Choh Hao Li. Part I", Int. J. Pept. Protein Res, vol. 32, no. 6 (published Dec 1988), pp. 417–598, doi:10.1111/j.1399-3011.1988.tb01371.x, PMID3073145
Hruby, V J (1988), "In memoriam Choh Hao Li, April 21, 1913-November 28, 1987", Int. J. Pept. Protein Res, vol. 31, no. 3 (published Mar 1988), pp. 253–4, PMID3286549
"Classic pages in Obstetrics and Gynecology. Interstitial cell stimulating hormone. II. Method of preparation and some physico-chemical studies, by Choh Hao Li, Miriam E. Simpson, and Herbert M. Evans. Endocrinology, vol. 27, pp. 803-808, 1940", Am. J. Obstet. Gynecol, vol. 17, no. 5 (published Nov 1, 1973), p. 716, 1973, PMID4599575
"Choh Hao Li", Triangle; the Sandoz Journal of Medical Science, vol. 9, no. 1, pp. 41–2, 1969, ISSN0041-2597, PMID4896971
Ingle, D J; Nezamis, J E; Moreley, E H; Li, C H (1953), "The effect of some partially purified preparations of corticotrophin upon the work performance of adrenalectomized-hypophysectomized rats", Acta Endocrinol, vol. 14, no. 2 (published Oct 1953), pp. 93–8, doi:10.1530/acta.0.0140093, PMID13113828
