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      • KCI등재후보

        국내 벤처기업의 성장요인 분석

        정진하 한국개발연구원 2005 KDI 政策硏究 Vol.27 No.1

        최근 대기업과 중소기업 간의 양극화가 심화되면서 중소기업의 경쟁력 강화가 중요한 경제 현안으로 대두하였다. 이와 관련하여 중소기업의 혁신을 주도해나가야 할 벤처기업에 대한 사회적 관심이 고조되고 있다. 또한 본격적인 벤처기업 지원정책이 시행된 지 10년 가까운 시간이 흐르면서 벤처생태계는 전략과제를 추론해볼 수 있을 만큼의 충분한 진화과정을 경험했다. 이러한 상황을 감안할 때 지금이 벤처생태계가 안고 있는 과제 및 벤처기업 지원정책의 바람직한 방향을 점검할 적절한 시점이라고 판단된다. 본 연구는 이러한 상황인식하에 향후 벤처기업 지원정책에 대한 정책적 시사점을 도출할 목적으로 벤처기업의 성장요인에 관한 실증분석을 하였다. 실증분석 결과 연구개발집약도가 높은 기업, 업력이 낮은 기업, 규모가 큰 기업, 정책자금 활용도가 높은 기업, 수도권에 위치한 기업의 경우 성장이 빠르게 나타난다. 벤처기업에 관한 국내 통계자료의 축적이 아직 미흡하고 통계자료의 신뢰도가 그리 높지 않기 때문에 본 연구는 분석의 한계를 지니고 있다. 향후 벤처기업정책 입안에 대한 연구의 기여도를 높이기 위해서는 통계자료의 체계적 축적이 필요하며, 보다 심도 있는 연구들이 뒤따라야 할 것이다. Strengthening the competitive edge of SMEs has become one of the most important economic issues in Korea as the bipolarization between large firms and SMEs has deepened. Accordingly, small innovative firms (referred as 'venture firms' in Korea) attract keen attention both from policy makers and academia. Also, we can sufficiently observe how the growth environment for venture firms has evolved, since it has been almost ten years after the Korean government started its support policy for venture firms. Considering this, now is the appropriate time to carry out an analysis of venture firms. From this point of view, this study looks at growth factors for venture firms to draw out policy implications. The empirical analysis shows interesting results. Firms with the following features all showed higher growth rates: firms with high R&D intensity, younger firms, bigger firms, firms using more policy loans, and firms located within and around the Seoul region. However, the empirical analysis has some limitations. The data used in the study is limited in terms of firm information and so there are some insufficiencies. Thus it is of great importance to compile the required data on firms to enable further in-depth studies.

      • KCI등재

        Biosynthesis and Control of Keratinase in Recalcitrant Feather-Degrading Bacillus megaterium F7-1

        정진하,전영동,김정도,박근태,손홍주,이나리,박기현 한국환경과학회 2010 한국환경과학회지 Vol.19 No.9

        This study was performed to investigate the nutritional conditions controlling keratinase activity in Bacillus megaterium F7-1. B. megaterium F7-1 produced keratinase using chicken feather as a sole source of carbon, nitrogen and sulfur. Addition of the feather medium with glucose enhanced keratinase production (68.9 U/ml), compared to control without glucose (63.2 U/ml). The synthesis of keratinase was repressed by addition of NH4Cl in B. megaterium F7-1. The highest keratinase production (70.9 U/ml) was obtained with the feather medium containing glucose and MgSO4·7H2O. Keratinase was produced in the absence of feather (4.9 U/ml), indicating its constitutive synthesis. Feather degradation resulted in free SH group formation. B. megaterium F7-1 effectively degraded chicken feather meal (86%), whereas duck feather, human nail, human hair and sheep wool displayed relatively low degradation rates (8-34%).

      • SCIESCOPUSKCI등재

        Cathepsin B1에 대한 Chloroquine 의 PH 의조직 저해영향

        정진하 한국생화학회 1991 BMB Reports Vol.24 No.4

        Cathepsin B1 was shown to be inhibited by chloroquine in a pH-dependent manner when α-N-benzoyl-DL-arginine-2-naphthylamide was used as substrate. Chloroquine at 1 mM inhibited the naphthylamidase activity of the enzyme by about 15, 30 and 50% at pH of 5, 6 and 7, respectively, and therefore its inhibitory activity seemed to be increasing with increased buffer pH. Such a pH-dependent inhibition by chloroquine appeared to be due to the increased affinity of the compound to cathepsin B₁ at higher pH, as shown by the preincubation and dialysis experiments and by kinetic analysis. Thus, chloroquine is likely to impair the intracellular protein breakdown by directly inhibiting one of the major lysosomal proteinases, cathepsin B₁, in addition to by raising the intralysosomal pH thereby inactivating the acid proteinases in lysosomes.

      • $\beta$-N-Acetyl-D-glucosaminidase A from Rat Uterus: Purification and Properties

        정진하,양철학,이우영,이희영,Jung, Jin-Ha,Yang, Chul-Hak,Lee, Woo-Young,Lee, Hee-Yong 생화학분자생물학회 1983 한국생화학회지 Vol.16 No.4

        성숙한 쥐의 자궁에서 $\beta$-N-acetyl-D-glucosaminidase A를 정제 하고 그 성질을 조사하였다. $\beta$-N-acetyl-D-glucosaminidase A는 암모니움 설페이트로 분리 한 뒤, DEAE-cellulose 컬럼, CM-cellulose 컬럼, Sephadex G-200 컬럼과 Concanavalin A-Sepharose 컬럼을 사용하여 정제한다. 이 효소는 443배로 정제되었고 최종적으로 24.5%의 수득률을 나타냈다. 잘 정제펀 효소는 전기 영동법에 의해 한개의 띠를 나타내었다. Sephadex G-200 컬럼에 의해 분자량을 측정한 결과 분자량은 119,000이었다. 이 효소는 pH 4.5에서 가장 큰 활동도를 나타냈고, Km 값은 1.7 mM로 나타났다. 이 효소는 $55^{\circ}C$에서 열에 매우 불안정함을 나타냈다. N-Acetyl-D-glucosamine, $\alpha$-methyl-D-mannoside, 초산이온, sulfite 이온은 이 효소의 활동도를 억제하고, NaCl 과소의 serum albumin은 활동도를 높여 주었다. 70%의 암모니움 설페이트 속에서 $-26^{\circ}C$로 7달 동안 얼린 효소는 93%의 활동도를 나타냈다. $\beta$-N-acetyl-D-glucosaminidase A (EC 3.2.1.30) was highly purified from the well matured rat uterus using the following sequence of steps; ammonium sulphate fractionation. DEAE-cellulose. CM-cellulose. Sephadex G-200, and Concanavalin A-Sepharose chromatographies. The specific activity of the purified enzyme was 4.9 units per mg of protein with 443 fold purification and, 24.5% yield of the enzyme activity. Disc gel electrophoresis showed one major protein band. The molecular weight of $\beta$-N-acetyl-D-glucosaminidase A was 119,000 by Sephadex G-200 chromatography. The enzyme had optimum activity at pH 4.5. Sodium chloride and bovine serum albumin activated the enzyme activity but $\beta$-N-acetyl-D-glucosamine, $\alpha$-methyl-D-mannoside, acetate, and sulphite inhibited the enzyme. The Km value was 1.7 mM with p-nitrophenyl-N-acetyl-$\beta$-D-glucosaminide as substrate. $\beta$-N-Acetyl-D-glucosaminidase A from rat uterus was unstable at $55^{\circ}C$. The crude enzyme obtained by ammonium sulfate fractionation was highly stable, showing 93% activity after 7 months at $-26^{\circ}C$.

      • pH-Dependent Inhibition of Cathepsin $B_1$ by Chloroguine

        정진하,Chung, Chin-Ha 생화학분자생물학회 1986 한국생화학회지 Vol.19 No.1

        Cathepsin $B_1$은 기질로써 $\alpha$-N-benzoyl-DL-arginine-2-naphthylamide가 사용될 때 pH-의존적으로 chloraquine에 의해 활성이 저해되었다. 1 mM chlaroquine은 pH 5, 6, 7에서 각각 이 효소의 활성도를 약 15, 30, 50%까지 저해하였다. 따라서 chloraquine의 저해도는 증가되는 완충액의 pH에 따라 비례적으로 증가함을 보인다. 이러한 chloroquine에 의한 pH-의존적인 저해성은 preincubatian이나 투석법 실험 그리고 활동도 분석에 의해 알 수 있는 것 같이 pH가 높아짐에 따라 cathepsin $B_1$에 대한 chlaroquine의 증가되는 친화력에 기인된다고 여겨진다. 그러므로 chloroquine은 lysosome내의 pH를 증가시킴으로 산성단백질 분해효소를 비활성화 시킬 뿐만 아니라 lysosome내의 주요한 단백질 분해효소 중의 하나인 cathepsin $B_1$을 직접적으로 저해시키기 때문에 세포 내부의 단백질 분해에 손상을 입힌다고 사료된다. Cathepsin $B_1$ was shown to be inhibited by chloroquine in a pH-dependent manner when $\alpha$-N-benzoyl-DL-arginine-2-naphthylamide was used as substrate. Chloroquine at 1 mM inhibited the naphthylamidase activity of the enzyme by about 15, 30 and 50% at pH of 5, 6 and 7, respectively, and therefore its inhibitory activity seemed to be increasing with increased buffer pH. Such a pH -dependent inhibition by chloroquine appeared to be due to the increased affinity of the compound to cathepsin $B_1$ at higher pH, as shown by the preincubation and dialysis experiments and by kinetic analysis. Thus, chloroquine is likely to impair the intracellular protein breakdown by directly inhibiting one of the major lysosomal proteinases, cathepsin $B_1$, in addition to by raising the intralysosomal pH thereby inactivating the acid proteinases in lysosomes.

      • KCI등재
      • KCI등재

        SMAD4 Controls Cancer Cell Metabolism by Regulating Methylmalonic Aciduria Cobalamin Deficiency (cbl) B Type

        정진하,유희민,박종호,김재연 한국분자세포생물학회 2022 Molecules and cells Vol.45 No.6

        Suppressor of mothers against decapentaplegic homolog (SMAD) 4 is a pluripotent signaling mediator that regulates myriad cellular functions, including cell growth, cell division, angiogenesis, apoptosis, cell invasion, and metastasis, through transforming growth factor β (TGF-β)-dependent and -independent pathways. SMAD4 is a critical modulator in signal transduction and functions primarily as a transcription factor or cofactor. Apart from being a DNA-binding factor, the additional SMAD4 mechanisms in tumor suppression remain elusive. We previously identified methyl malonyl aciduria cobalamin deficiency B type (MMAB) as a critical SMAD4 binding protein using a proto array analysis. This study confirmed the interaction between SMAD4 and MMAB using bimolecular fluorescence complementation (BiFC) assay, proximity ligation assay (PLA), and conventional immunoprecipitation. We found that transient SMAD4 overexpression down-regulates MMAB expression via a proteasome-dependent pathway. SMAD4-MMAB interaction was independent of TGF-β signaling. Finally, we determined the effect of MMAB downregulation on cancer cells. siRNA-mediated knockdown of MMAB affected cancer cell metabolism in HeLa cells by decreasing ATP production and glucose consumption as well as inducing apoptosis. These findings suggest that SMAD4 controls cancer cell metabolism by regulating MMAB.

      • KCI등재

        개념 설계 평가를 위한 제품 품질지수

        정진하,박영원,Jeong, Jin-Ha,Park, Young-Won 한국생산제조학회 2010 한국생산제조학회지 Vol.25 No.6

        A product system will be improved continually until requirements are satisfied. It is true that considering alternative designs to improve product system is hard work; it is also true that selecting an adequate design idea that represents the needs of stakeholders concerned and meets effectiveness factors properly is not an easy work, either. In the process of driv-ing an idea and designing, which is called Design Phase, there are lots of existing tools for testing the driven idea in DFSS. But, those kinds of tools do not offer the function that helps to select the technically better design idea among alternative design ideas that have the same evaluation level. Moreover it is inappropriate to select adequate alternative design ideas by just verifying only the evaluation table in pugh matrix, since satisfied deviation val-ues are low when there is a too competitive mass product system in a market. Also, for the IT product with short life cycle, faster and more effective testing tool is needed. Therefore, the 'roduct quality index' is suggested in order to select an appropriate candidate design concept for system development that meets requirements by using 'deality concept' pro-vided by TRIZ. According to the result of this research, it is possible to select technically better idea fast and effectively; it is confirmed by applying the approach to the case of LCD BLU (Back Light Unit).

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