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L C Smith

Publications and source records attributed to L C Smith.

At least 73 records · Page 4Linked to original sources
PubMed1997

Mitochondrial genotype segregation in a mouse heteroplasmic lineage produced by embryonic karyoplast transplantation.

Mitochondrial genotypes have been shown to segregate both rapidly and slowly when transmitted to consecutive generations in mammals. Our objective was to develop an animal model to analyze the patterns of mammalian mitochondrial DNA (mtDNA) segregation and transmission in an intraspecific heteroplasmic maternal lineage to investigate the mechanisms controlling these phenomena. Heteroplasmic progeny were obtained from reconstructed blastocysts derived by transplantation of pronuclearstage karyoplasts to enucleated zygotes with different mtDNA. Although the reconstructed zygotes contained on average 19% mtDNA of karyoplast origin, most progeny contained fewer mtDNA of karyoplast origin and produced exclusively homoplasmic first generation progeny. However, one founder heteroplasmic adult female had elevated tissue heteroplasmy levels, varying from 6% (lung) to 69% (heart), indicating that stringent replicative segregation had occurred during mitotic divisions. First generation progeny from the above female were all heteroplasmic, indicating that, despite a meiotic segregation, they were derived from heteroplasmic founder oocytes. Some second and third generation progeny contained exclusively New Zealand Black/BINJ mtDNA, suggesting but not confirming, an origin from an homoplasmic oocyte. Moreover, several third to fifth generation individuals maintained mtDNA from both mouse strains, indicating a slow or persistent segregation pattern characterized by diminished tissue and litter variability beyond second generation progeny. Therefore, although some initial lineages appear to segregate rapidly to homoplasmy, within two generations other lineages transmit stable amounts of both mtDNA molecules, supporting a mechanism where mitochondria of different origin may fuse, leading to persistent intraorganellar heteroplasmy.

Animals↗
PubMed1997

Effects of inhibin A and activin A during in vitro maturation of bovine oocytes in hormone- and serum-free medium.

The aim of this study was to investigate whether inhibin A and/or activin A play a role in the acquisition of oocyte competence during the final stages of oogenesis. The particular goal was to establish whether inhibin A and activin A exert development-enhancing effects during in vitro maturation in serum-free media and whether such effects are related to changes in the kinetics of meiotic resumption and/or fertilization rates. Cumulus-oocyte-complexes (COCs) were matured in two control media (Medium 199 [M199] with hormones and serum, hormone-serum control; M199 + 0.6% BSA, BSA-control) and nine treatment media (M199 with 0.6% BSA containing 100, 10, and 1 ng/ml of recombinant human inhibin A, recombinant human activin A, and the combination of the two). Oocytes were fertilized and cultured using standard procedures. Cleavage was assessed at 54 h and blastocyst development at 8 days after in vitro fertilization. Kinetics of oocyte maturation and the fertilization rates were evaluated after fixing and staining (Hoechst 33342) of oocytes at 8, 16, and 22 h after onset of in vitro maturation or of presumptive zygotes at 12 h after in vitro fertilization, respectively. Although there was no effect on cleavage rates, inhibin A and activin A significantly enhanced postcleavage development at concentrations of 10 ng/ml (57.7 +/- 7.5% and 56.6 +/- 11.7%, respectively) and 100 ng/ml (50.6 +/- 18.6% and 56.4 +/- 4.0%, respectively) compared to that in the BSA-control group (24.6 +/- 3.2%). Whereas inhibin A- and activin A-treated oocytes showed development-enhancing effects similar to those in the hormone-serum controls, these groups differed with regard to the kinetics of meiotic resumption. Likewise, the enhanced development of the hormone-serum control and the inhibin A/activin A-treated oocytes was not related to increased fertilization rates relative to the BSA-control. These results suggest that inhibin A and activin A may play important roles during the final stages of oogenesis and that recombinant inhibins and activins are useful compounds for the development of a serum-free culture system for in vitro maturation of oocytes from cattle and possibly other mammalian species.

Activins↗
PubMed1997

Synchronization of cell division in eight-cell bovine embryos produced in vitro: effects of 6-dimethylaminopurine.

The methods used to achieve blastomere cell cycle synchronization in embryos used as nuclear donors during embryo reconstruction have been largely unsuccessful. The aim of this study was to determine the reliability of 6-dimethylaminopurine (6-DMAP), an inhibitor of maturation promoting factor, to half and to synchronize blastomere division in cleavage stage bovine embryos. A second goal was to assess its reversibility and toxicity in vitro. Eight-cell stage embryos obtained at 58 h after insemination were treated with several concentrations of 6-DMAP for 12 h. Treated embryos were assessed for cleavage arrest, chromatin morphology, DNA synthesis, histone H1 and scored for blastocyst formation and for hatching rate. They were subsequently fixed and the number of nuclei counted. Complete arrest of cell division was observed at concentrations of 3 mmol 6-DMAP l-1 and above. At these concentrations, interphase nuclei in arrest were noticeably larger compared with interphase nuclei of eight-cell control embryos. Removal from 6-DMAP led to release from cleavage arrest and was followed by synchronized mitosis, histone H1 kinase deactivation and re-entry into interphase within 4-5 h. Twenty-nine per cent of interphase nuclei were synthesizing DNA at the end of the 12 h treatment as indicated by BrdU analysis. At 2 h after removal from 6-DMAP, an abrupt decrease to 9% BrdU-positive nuclei was observed followed by an increase to 39% by 6 h and a decrease to 28% at 10 h. The ability of treated embryos to reach the blastocyst stage in vitro and the number of cells per blastocyst were reduced. These results indicate that 6-DMAP can reversibly arrest and synchronize cleavage to the fifth cell cycle in eight-cell bovine embryos. Although a decrease was observed in the proportion of blastocysts obtained after treatment, it is concluded that 6-DMAP is a useful tool for synchronization studies requiring donor nuclei at metaphase before fusion to recipient oocyte.

Adenine↗
PubMed1996

Effect of the apolipoprotein C-II/C-III1 ratio on the capacity of purified milk lipoprotein lipase to hydrolyse triglycerides in monolayer vesicles.

The effect of the apolipoprotein C-II/C-III1 ratio on the capacity of purified bovine milk lipoprotein lipase to hydrolyse triglycerides was measured in a controlled model of pyrene-labeled nonanoyltriglycerides (1-2 ditetradecyl 3-pyrene nonanoyl glyceride) monolayer vesicles. Monolayer was composed of triglycerides, a non-hydrolysable phospholipid ether and cholesterol, a model system where the quality of the interface can be controlled. LPL released fatty acids from pyrene-triglycerides which were transferred from the lipoprotein structure to albumin. This transfer induces a decrease in the excimer production and in the excimer fluorescence intensity. Apolipoprotein C-II and C-III0 and C-III1 were purified from apolipoprotein VLDL. The 2 fragments, C-III1 A (peptide 1-40) and C-III1 B (peptide 41-79), were obtained after thrombin cleavage. Apolipoproteins C-III0 and C-III1 had a similar inhibitory effect on LPL. Inhibition with apo C-III0 or apo C-III1 was 85% of full LPL activity without inhibitor: Apo C-III1 B inhibited 62% of basal activity. It was 27% less effective than apo C-III1. Fragment C-III1 A did not inhibit LPL. The effect of change in both apo C-II (0-0.6 microM) and apo C-III1 (0-1.0 microM) on triglyceride hydrolysis shows the importance of the apo C-II/C-III1 ratio for the release of free fatty acids from triglycerides by LPL. The activating effect of apo C-II in the absence of the apo C-III inhibitor was maximal at 0.06 microM. No further activation was obtained between 0.06 and 0.30 microM. Higher concentrations decreased LPL activity. Apo C-III1 (0.1 microM) decreased the maximum activation by apo C-II from 0.0196 to 0.063 nmol/min/nmol LPL. Higher concentrations of apo C-III1 (0.1-0.5 microM) required higher apo C-II concentrations (0.30 microM instead of 0.06 microM) for maximal activation than when apo C-III1 was absent. The activity of the enzyme without apo C-II was decreased by 65% by 0.12 microM apo C-III1. Increasing the apo C-II/apo C-III1 ratio from 0.1 to 1, increased the activation of the enzyme by a given apo C-II concentration. Moreover, for a given apo C-II/C-III1 ratio, the LPL activation increased with the apo C-II concentration (between 0 and 0.010 microM), until a plateau was reached. This is important, as the change in the C-II/C-III1 ratio is not the only factor affecting LPL activity, and inhibition by apo C-III1 also depends on the overall quantity of apolipoproteins. Extrapolation of these results suggests that hyperlipoproteinemia seems to be more likely due to overproduction of VLDL, than to a decrease in lipoprotein lipase activity.

Animals↗
PubMed1996

Structure-function relationship of lipoprotein lipase-mediated enhancement of very low density lipoprotein binding and catabolism by the low density lipoprotein receptor. Functional importance of a properly folded surface loop covering the catalytic center.

We examined the structure-function relationship of human lipoprotein lipase (hLPL) in its ability to enhance the binding and catabolism of very low density lipoproteins (VLDL) in COS cells. Untransfected COS cells did not bind to or catabolize normal VLDL. Expression of wild-type hLPL by transient transfection enhanced binding, uptake, and degradation of the VLDL (a property of LPL that we call bridge function). Heparin pretreatment and a monoclonal antibody ID7 that blocks LDL receptor-binding domain of apoE both inhibited binding, and apoE2/E2 VLDL from a Type III hyperlipidemic subject did not bind. However, LDL did not reduce 125I-VLDL binding to the hLPL-expressing cells, whereas rabbit beta-VLDL was an effective competitor. By contrast, LDL reduced uptake and degradation of 125I-VLDL to the same extent as excess unlabeled VLDL or beta-VLDL. These data suggest that binding occurs by direct interaction of VLDL with LPL but the subsequent catabolism of the VLDL is mediated by the LDL receptor. Mutant hLPLs that were catalytically inactive, S132A, S132D, as well as the partially active mutant, S251T, and S172G, gave normal enhancement of VLDL binding and catabolism, whereas the partially active mutant S172D had markedly impaired capacity for the process; thus, there is no correlation between bridge function and lipolytic activity. A naturally occurring genetic variant hLPL, S447-->Ter, has normal bridge function. The catalytic center of LPL is covered by a 21-amino acid loop that must be repositioned before a lipid substrate can gain access to the active site for catalysis. We studied three hLPL loop mutants (LPL-cH, an enzymatically active mutant with the loop replaced by a hepatic lipase loop; LPL-cP, an enzymatically inactive mutant with the loop replaced by a pancreatic lipase loop; and C216S/C239S, an enzymatically inactive mutant with the pair of Cys residues delimiting the loop substituted by Ser residues) and a control double Cys mutant, C418S/C438S. Two of the loop mutants (LPL-cH and LPL-cP) and the control double Cys mutant C418S/C438S gave normal enhancement of VLDL binding and catabolism, whereas the third loop mutant, C216S/C239S, was completely inactive. We conclude that although catalytic activity and the actual primary sequence of the loop of LPL are relatively unimportant (wild-type LPL loop and pancreatic lipase loops have little sequence similarity), the intact folding of the loop, flanked by disulfide bonds, must be maintained for LPL to express its bridge function.

Animals↗
PubMed1996

Effects of cell-cycle-arrest agents on cleavage and development of mouse embryos.

In mammals, there are no reliable methods for synchronizing cell division of early embryos without reducing their ability to develop into blastocysts and fetuses. The present study was undertaken to examine the in vitro inhibition of cell division of four-cell mouse embryos by cell cycle arrest agents. The reversibility of the agents was also tested by examining the developmental ability of treated embryos. Four-cell mouse embryos obtained at 54 hr post-human chorionic gonadotrophin (post-hCG) were cultured for 4, 8, 12, or 16 hr in media supplemented with either nocodazole, an inhibitor of tubulin polymerization, 6-dimethylaminopurine (6-DMAP), an inhibitor of maturation promoting factor (MPF) activation, or aphidicolin, a specific inhibitor of DNA polymerase alpha. Reversibility and toxicity of these agents were both dose and time dependent. For all three agents, prolonging cleavage arrest for 8 or 16 hr (at the effective concentrations) caused embryo lethality. Although nocodazole treatment was least cytotoxic, 6-DMAP and aphidicolin concentrations which induce cleavage arrest were detrimental to development beyond the blastocyst stage. The results of this study show that the development of embryos treated with these three cell-cycle-arrest agents is dose and incubation time dependent. Toxic effects beyond the blastocyst stage could only be minimized for nocodazole by reducing the exposure time of treatment and concentration of the mitotic inhibitor. However, these results render doubt on the usefulness of 6-DMAP and aphidicolin for synchronization studies leading to embryo transfer procedures.

Adenine↗
PubMed1996

Sea urchin genes expressed in activated coelomocytes are identified by expressed sequence tags. Complement homologues and other putative immune response genes suggest immune system homology within the deuterostomes.

To identify some of the genes expressed in LPS-activated coelomocytes, we sequenced randomly chosen clones from a directionally constructed cDNA library to produce a set of expressed sequence tags (ESTs). Deduced amino acid sequences from 307 ESTs were compared with known protein sequences in GenBank, and significant matches to approximately 30% of the clones were identified. Eighty-nine clones matched to 55 different proteins, including several putative immune effector proteins. In this work, we show the first identification of an invertebrate homologue of a vertebrate C component. Another EST matches to several short consensus repeats that are characteristic of a variety of proteins, including CR/regulatory proteins and clotting factors. Additional putative immune effector genes include 1) a Kazal-type protease inhibitor that may function to inactivate bacterial proteases, 2) a C-type lectin similar to echinoidin, and 3) a serine protease with similarities to thrombin, elastase, haptoglobin, and plasmin. Other EST categories include 1) cell surface proteins and receptors, 2) proteins involved in signaling systems, 3) lysosomal and secreted proteins, 4) cytoskeletal and cytoskeletal modifying proteins, 5) general cell function proteins, 6) proteins with unknown function, and 7) ESTs without significant matches, 25 with open reading frames. Many of the ESTs identified in this study represent the types of genes expected to be used in lower deuterostome immune functions.

Amino Acid Sequence↗
PubMed1996

Synchronization of cell division in eight-cell bovine embryos produced in vitro: effects of nocodazole.

Current methods of arresting and synchronizing cell division have not been very successful and have had few applications in embryo studies. Our objective was to determine the reliability of a metaphase arrest agent, nocodazole, for halting and synchronizing blastomere division in cleavage-stage bovine embryos, and to verify its reversibility and toxicity in vitro. Eight-cell-stage embryos obtained at 58 hr postinsemination were treated with varying concentrations of nocodazole for 12 hr. Treated embryos were assessed for cleavage arrest, chromatin morphology, DNA synthesis, and histone H1 and myelin basic protein (MBP) kinase activity, and were scored for blastocyst formation and hatching rate. They were subsequently fixed to count the number of nuclei. Complete arrest of cell division was observed at concentrations of 0.4 micrograms ml-1 and above. Removal from nocodazole treatment led to immediate release from cleavage arrest, and was followed by synchronized mitosis, histone H1 kinase deactivation, and reentry into interphase within 3-5 hr. DNA synthesis was reinitiated at 6 hr after release. Although cell numbers and hatching rate decreased, the proportion of embryos reaching blastocyst stage was not significantly affected in nocodazole-treated embryos. It is concluded that nocodazole is a suitable choice for the cell-cycle synchronization of donor embryos for use in studies on the interactions between nucleus and cytoplasm during early embryogenesis.

Animals↗
PubMed1996

Neuropsychological rehabilitation of mild traumatic brain injury.

A significant minority of patients who have sustained a mild traumatic brain injury (MTBI) may exhibit persistent disability. There have been few attempts to describe and evaluate the effectiveness of neurorehabilitation for these patients. We conducted a retrospective analysis of the results of a neuropsychological rehabilitation programme for 20 patients with MTBI. Based upon the ability to resume productive functioning after treatment, 10 patients were determined to exhibit a good outcome and 10 patients were considered to exhibit a poor outcome. Patients with good outcome exhibited significant pre-post-treatment improvements on both neuropsychological measures of cognitive functioning and self-reported post-concussive symptoms. Patients with poor outcome demonstrated little improvement in either area, and in some cases showed a decline in functioning. The results are consistent with the view that there may be significant variability in recovery and response to treatment after MTBI. There is a continued need to identify which patients may benefit from neurorehabilitation, develop specially tailored interventions, and conduct controlled, prospective studies in this area.

Adult↗
PubMed1996

Sequence comparison of mitochondrial tRNA genes and origin of light strand replication in Bos taurus and Nellore (Bos indicus) breeds.

Although the complete bovine mitochondrial DNA molecule has been previously sequenced and sequence comparisons of the mitochondrial displacement loop have been performed, detailed sequence information is limited on coding regions of mitochondrial DNA within and among breeds of Bos taurus and Bos indicus. This study analysed polymorphism of the mitochondrial DNA transfer RNA genes for tryptophan, alanine, asparagine, cysteine, tyrosine and the origin of light strand replication among Ayrshire, Canadian, Belgium Blue, Brown Swiss, Hereford, Jersey, Limousine, Piedmontaise, Red Angus, Simmental (Bos taurus) and a Nellore (Bos indicus). Nucleotide sequence analysis of a 420-bp fragment of mitochondrial DNA comprising the five transfer RNA genes showed 100% homology among single individuals of the Bos taurus breeds. The Nellore breed showed guanine to adenine substitutions in the DHU arm of asparagine tRNA and in the origin of light-strand replication. This equates to a 0.5% sequence difference between the Nellore and Bos taurus breeds and may reflect an independent evolutionary origin of the species.

Animals↗
PubMed1996

Oocyte quality in small antral follicles in the presence or absence of a large dominant follicle in cattle.

The aim of these experiments was to determine whether the presence of a dominant follicle affects the developmental competence of oocytes from small antral follicles of cattle. In Expt 1, oocytes or follicular fluid samples were collected from follicles 2-7 mm in diameter before (day 3 of the oestrous cycle; n = 4) or after (days 6 and 7 of the oestrous cycle; n = 6) emergence of the first wave dominant follicle (verified by rectal ultrasonography). Five to ten follicles were aspirated for the determination of individual follicular fluid concentrations of oestradiol, progesterone, testosterone and dimeric inhibin; oocytes from the remaining follicles from each cow were pooled and developmental capacity assessed by in vitro fertilization and maturation. In Expt 2, ovaries containing a young corpus luteum and with or without a large oestrogen-active follicle were collected from the abattoir. Follicular aspirates from small follicles in each pair of ovaries were pooled, and oocyte quality and steroid concentrations were determined. In Expt 1, small follicles obtained before emergence of the dominant follicle contained significantly more oestradiol than they did after emergence (19.5 +/- 1.5 versus 0.7 +/- 1.1 ng ml-1, respectively; P < 0.05), but there were no significant differences in concentrations of progesterone, testosterone or dimeric inhibin. The percentage of blastocysts obtained from oocytes collected before (12.1 +/- 9.0) or after emergence (11.8 +/- 7.0) of the dominant follicle did not differ significantly (P > 0.05). In Expt 2, follicular steroid concentrations did not differ in small follicles taken in the presence versus the absence of a large oestrogen-active follicle, and there were no differences in the developmental capacity of the oocytes. There were significant negative correlations between follicular oestradiol concentration and the percentage of blastocysts formed from two-cell (r = -0.90; P < 0.01) and eight-cell embryos (r = -0.65; P < 0.05). These data suggest that in cattle the developmental competence of oocytes from small antral follicles is not adversely affected by the presence of a dominant follicle.

Animals↗
PubMed1996

Osteoarticular tuberculosis.

Over the past several years there has been a dramatic rise in the incidence of tuberculosis. Peripheral skeletal tuberculosis is, more often than not, misdiagnosed as osteoarthritis or pyogenic osteomyelitis. Tuberculosis is no longer a "zebra" among differential diagnoses. This article reviews the pathogenesis, along with practical tips for the diagnosis and treatment of osteoarticular tuberculosis.

Aged↗
PubMed1996

Interdisciplinary multiinstitutional alliances in support of educational programs for health sciences librarians.

This project responds to the need to identify the knowledge, skills, and expertise required by health sciences librarians in the future and to devise mechanisms for providing this requisite training. The approach involves interdisciplinary multiinstitutional alliances with collaborators drawn from two graduate schools of library and information science (University of Illinois at Urbana-Champaign and Indiana University) and two medical schools (University of Illinois at Chicago and Washington University). The project encompasses six specific aims: (1) investigate the evolving role of the health sciences librarian; (2) analyze existing programs of study in library and information science at all levels at Illinois and Indiana; (3) develop opportunities for practicums, internships, and residencies; (4) explore the possibilities of computing and communication technologies to enhance instruction; (5) identify mechanisms to encourage faculty and graduate students to participate in medical informatics research projects; and (6) create recruitment strategies to achieve better representation of currently underrepresented groups. The project can serve as a model for other institutions interested in regional collaboration to enhance graduate education for health sciences librarianship.

Cooperative Behavior↗
PubMed1996

A novel DNA-peptide complex for efficient gene transfer and expression in mammalian cells.

To develop a nonviral gene delivery system for treatment of diseases, our strategy is to construct DNA complexes with short synthetic peptides that mimic the functions of viral proteins. We have designed and synthesized two peptides which emulate viral functions - a DNA condensing agent, YKAK(8)WK, and an amphipathic, pH-dependent endosomal releasing agent, GLFEALLELLESLWELLLEA. The active gene delivery complex was constructed step-wise through a spontaneous self-assembly process involving oppositely charged, electrostatic interactions. To assemble DNA-peptide complexes with different overall net charges, only the negative charges of DNA phosphate, the positive charges of the 10 epsilon-amino groups of YKAK(8)WK and the negative charges of the 5 gamma-carboxyl groups of GLFEALLELLESLWELLLEA were considered. In the first step, negatively charged DNA was rapidly-mixed with an excess of YKAK(8)WK to form positively charged DNA-YKAK(8)WK complexes, which gave little gene transfer. In the second step and to form the active complex,the cationic DNA complex was rapidly mixed with spontaneously incorporated through electrostatic interactions. Transfection using these complexes of CMV-luc, YKAK(8)WK and GLFEALLELLESLWELLLEA gave high-levels of gene expression in a variety of cell lines. These simple DNA complexes, which contain only three molecularly defined components, have general utility for gene delivery and can replace viral vectors and cationic lipids for some applications in gene therapy.

Amino Acid Sequence↗
PubMed1995

Assembly of somatic histone H1 onto chromatin during bovine early embryogenesis.

We have examined the distribution of somatic histone H1 in bovine oocytes and preimplantation embryos, using an antibody that recognizes histone H1 subtypes present in somatic cells. Immunoreactive H1 was not detectable on the chromosomes of metaphase II of meiosis nor in the nuclei of early cleavage-stage embryos. In most embryos, immunoreactive H1 was assembled onto embryonic chromatin during the fourth to sixth cell cycle after fertilization. No immunoreactive somatic histone H1 was detected, however, when embryos were incubated in the presence of alpha-amanitin beginning early during the fourth cell cycle. These results indicate that somatic subtypes of histone H1 are assembled onto embryonic chromatin in a developmentally regulated manner that requires embryonic transcription. Aphidicolin, an inhibitor of DNA replication, also inhibited the assembly of somatic histone H1 onto chromatin when present at early stages of the 4th cell cycle. It is suggested that, because the bulk of histone gene expression in proliferating cells occurs during DNA replication, expression of genes encoding immunoreactive H1 is inhibited in embryos blocked before or soon after entering the S-phase. These findings on the control of somatic histone H1 assembly onto chromatin in cattle show a remarkable similarity to those found in the mouse. Such evolutionary conservation suggests that the somatic histone H1 complement of chromatin may regulate critical aspects of chromatin activity during mammalian oogenesis or early embryogenesis.

Animals↗
PubMed1995

Lipoprotein lipase: role of intramolecular disulfide bonds in enzyme catalysis.

Lipoprotein lipase (LPL) catalyzes the hydrolysis of the triacylglycerol component of triacylglycerol-rich lipoproteins. There are 4 cysteine pairs that are completely conserved among LPLs of all species known. We examined the functional importance of each of the cysteine pairs in enzyme catalysis by examining LPLs produced in Cos cells by transfection. Immunoreactive LPL was produced by vectors encoding the wildtype LPL and each of the 4 cysteine-pair mutant LPLs. Enzyme activity was detectable in the wildtype enzyme, but not in 3 of the 4 Cys-->Ser mutant enzymes (C216S/C239S, C264S/C275S, and C278S/C283S). Interestingly, LPL activity was also present in the mutant (C418S/C438S), which affects the C-terminal cysteine pair, with a specific activity approximately 50% higher than that of wildtype. There is evidence that LPL contains two distinct domains consisting of the N-terminal three-quarters of the sequence connected by a flexible region to the C-terminal domain comprising the rest of the molecule. The conservation of catalytic function despite the disruption of the only disulfide bridge in the C-terminal domain of LPL indicates that the two domains can function independently of each other in enzyme catalysis.

Amino Acid Sequence↗