PRIMARY STRUCTURE OF HUMAN SKELETAL GROWTH-FACTOR - HOMOLOGY WITH HUMAN INSULIN-LIKE GROWTH FACTOR-II
PRIMARY STRUCTURE OF HUMAN SKELETAL GROWTH-FACTOR - HOMOLOGY WITH HUMAN INSULIN-LIKE GROWTH FACTOR-II
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DOI：
10.1016/0304-4165(88)90127-4
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发表时间：
1988-07-14
期刊：
影响因子：
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通讯作者：
BAYLINK, DJ
中科院分区：
文献类型：
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作者：
MOHAN, S;JENNINGS, JC;BAYLINK, DJ
采用羟基磷灰石层析、凝胶过滤、FPLC肝素- sepharose亲和层析和反相高效液相色谱法对人骨中提取的人骨生长因子（Human skeletal growth factor， SGF）进行纯化。除了每种制备中约30%的SGF分子缺乏n端丙氨酸外，人类SGF是均匀的。75%的人类SGF序列已经确定。n端20个氨基酸和几个色氨酸片段的氨基酸序列与从血清中纯化的人胰岛素样生长因子- ii （IGF-II）的相应序列相同。然而，由于人类SGF的c肽（可变区）尚未测序，我们无法得出SGF与IGF-II相同的结论。将人SGF的氨基酸序列与文献中描述的IGF-II变体的氨基酸序列进行比较，发现人SGF不是已知的IGF-II变体之一。在人骨提取物中也发现了igf - 1，但其含量比SGF/IGF-II少几倍。SGF/IGF-II的相对丰度。骨中SGF/IGF-II和IGF-I的相对丰度与体外人骨细胞产生这两种丝裂原的相对速率相对应。关于IGF-II在骨中的生理意义，以往对SGF体外生物学作用的研究表明，该生长因子对成骨细胞系细胞具有旁分泌和自分泌两种功能。此外，我们提出SGF是骨形成与骨吸收耦合的中介，是一种重要的骨体积调节机制。由于SGF与IGF-II非常相似（如果不完全相同），因此SGF在骨中的这些拟议的调节功能似乎可能归因于IGF-II。
Human skeletal growth factor (human SGF) extracted from human bone has been purified to homogeneity by hydroxyapatite chromatography and gel filtration under dissociative conditions followed by FPLC heparin-Sepharose affinity chromatography and reverse phase HPLC. Human SGF was homogeneous except that in each preparation about 30% of SGF molecules lacked the N-terminal alanine. 75% of the human SGF sequence has been determined. The amino acid sequences of the N-terminal 20 amino acids and of several tryptic fragments were identical to the corresponding sequences of human insulin-like growth factor-II (IGF-II) purified from serum. However, since the C-peptide (variable region) of human SGF has not yet been sequenced, we cannot conclude that SGF is identical to IGF-II. Comparison of the amino acid sequence of human SGF with that of IGF-II variants that have been described in the literature revealed that human SGF is not one of the known IGF-II variants. IG-I was also found in human bone extract but was several-fold less abundant than SGF/IGF-II. The relative abundance of SGF/IGF-II. The relative abundance of SGF/IGF-II and IGF-I in bone corresponded to the relative rates of production of these two mitogens by human bone cells in vitro. Regarding the physiologial significance of IGF-II in bone, previous studies on the biological actions of SGF in vitro suggest that this growth factor can have both paracrine and autocrine functions on cells of the osteoblast line. In addition, we have proposed the concept that SGF is a mediator of the coupling of bone formation to bone resorption, an important bone volume regulatory mechanism. In as much as SGF is very similar (if not identical) to IGF-II, it seems likely that these proposed regulatory functions of SGF in bone are attributable to IGF-II.